So I have two ASOIAF ideas that I am debating between.
The first is an SI into the younger brother of Aegon the Conqueror, save that the SI has zero knowledge of ASOIAF/GoT. The biggest changes to canon would be 1) the SI weds Visenya, 2) the SI ends up Lord of the Vale, and 3) the significantly different political structure that the Targaryen's enforce thanks to the SI's out of universe knowledge.
As someone with a modern education in history and political science, along with a much broader knowledge base to draw upon, the SI is opposed to a conquest without a solid plan for the future and plan to secure Targaryen rule going forward.
One of the biggest changes is that instead of setting out to reform the faith or co-opt it, the Dragons deliberately set out to break the Faith. The SI refuses to allow them to have any role in crowning a Targaryen monarch, legitimizing their marriages, or otherwise having any political power. His belief is that the Faith is never going to quietly acquiesce to the Conquest, even if the dragons were willing to actively cooperate with them, and so it is best to break the faith as part of the initial conquest than having to deal with a civil war down the road. As part of this, the Targaryens deliberately offend against the Faith and even, when the High Septon counsels peace, have him assassinated - although I'm not sure that I would actually have him oppose holy war in this, the Targaryens are being offensive enough that it would be essentially politically impossible for him to ever accept the Targaryens terms or advocate bending the knee to the "foreign invaders".
The same with the power of the nobles. With the conquest of the Riverlands and Stormlands, the nobles of those two realms all swore fealty and the Dragons take the opportunity once they inevitably break faith because of the Faith's holy war, to establish the precedent for breaking fealty to the Dragons; the dragons show up and the keeps residents have twenty four hours to hand over everyone of the lords blood (or their heads) or the entire keep gets burned to ash along with everyone inside.
Politically, the biggest difference from canon going forward is the succession for the Iron Throne. It is made explicit that to be a potential heir to the throne you must have a living dragon bound to you. If your dragon dies after you ascend to the throne then that is one thing, but without a living dragon you aren't in contention for the throne; period. After that, ascending the throne is done in two ways. The current Archon (king by a different name) can nominate a successor and every living dragon rider gets a vote (must have a currently living dragon to get a vote), with a simple majority vote the nominee becomes the confirmed heir and on the Archon's passing or abdication said heir ascends unless a two thirds vote of living dragonriders votes to oppose the ascension. If there is no confirmed heir and an open throne then a vote of the dragonriders is held, if anyone of them gets two thirds in favor then they become Archon. If no one gets two thirds then the two with the fewest votes can either renounce their claim (one or both) or fight to the death in single combat (well each of them also gets their dragon), once the contest is completed the vote is held again. Repeat until there is only one candidate left or someone gets the requisite two thirds vote.
Dragonstone is turned into the personal domain of the Targaryen's with no one save them allowed to leave the island, it is also where the dragons without riders reside (not in Kings Landing). The eldest Targaryen who is not the Archon or Lord of the Vale is named the Lord of Dragonstone and has absolute authority over it but must forever renounce any other title and isn't allowed to leave the Island as a general rule. Absent a secret, emergency, cache in the Vale all dragon eggs remain on Dragonstone and it is considered high treason to remove them from the island. It is also considered high treason for anyone not acknowledged a Targaryen to bond a dragon.
All pregnant female Targaryens are brought to Dragonstone and remain there until the birth. After birth, the babe is baptised in dragon fire. If you survive then you are acknowledged a Targaryen (regardless of who the actual father of the babe is). If the mother refuses (for example, married to a non-Targaryen) then the baptism doesn't occur but the babe is forever removed from any Targaryen related claim.
Targaryen children generally spend the first sixteen years of their lives residing on Dragonstone and being educated there. With dragons making travel relatively trivial, visits by (or too) parents are both common and easy but Targaryen children are generally raised communally among one another, educated by their own scholars and instructors and isolated from the Maesters, Septons, etc. Once they are sixteen they go back to their parents to learn whatever particulars are needed to assume their future lordships and establish relationships with their future vassals.
Targaryens are expected to retire at the age of sixty five. Upon reaching that age they abdicate (including the Archon) unless a majority vote of dragon riders decides otherwise (upon the individual's petition).
Let's see, other things.
1) The Starks, after bending the knee, are titled the Prince/Princess of Winter in acknowledgement of their royal history in the north and are considered the highest ranking nobility in the order of precedence after the Targaryens. The North also bows far sooner. Torrhen Stark called the banners once he heard the Dragons were conquering the Riverlands, they cross the Neck while the SI & Visenya are still securing the Vale and so are met by two (not three) dragons. Brandon Snow is a Greenseer and while his visions show him that he could successfully kill the two dragons present, they also show that the response would be Aelyx (the SI) & Visenya flying North on their dragons and (often under cover of darkness) simply putting every castle, town, village, holdfast, forest, and field to dragon flame; they would come North not to conquer but to genocide in response to their siblings deaths and the deaths of their dragons. So instead he counsels peace.
The Old Gods aren't seen as a threat to the Targaryens (no real organization and a much more acceptable belief system) so they see zero issue courting the First Men over than Andals. Aelyx & Visenya agree to have one of their future children marry one of the children of Torrhen (or his successor) to cement the alliance. When the child of that pairing results in a dragonrider who can warg with their bonded dragon, it becomes relatively common practice for intermarriages between the Starks and the Targaryens to occur.
The pairing is Aleyx & Visenya's daughter with the grandson of Torrhen (Alaric, his eldest grandson already being married)
2) The Targaryens don't get around to the Iron Isles until around 20 AC as they are distracted securing their conquests (much less bending the knee and much more active pacification required than in canon given the religious war and that the Arryns were deposed instead of surrendering). The pairing of Alaric & Daenerys has produced a son who can warg with his dragon, and so when the Iron Isles are conquered Alaric is raised up as Prince of Iron. They are also given some of the Westerlands (Faircastle, Castamere, The Crag, etc.) & Riverlands (The Twins & Seagard). Succession for this title isn't special save that the one holding it (or their heir and spouse) is barred from holding royal title.
2) The Arryns get deposed. Less because of a specific need to do so than because an excuse to do so could be easily manufactured (their refusal to bend the knee when called upon to do so) and the SI needed a title/lands commiserate with his position (which basically meant a Lord Paramount). Of the options, he chose the Vale because of its position and because of the Eyrie - with dragons it becomes utterly impossible to conquer and controlling the Vale is a great way to ensure that the North, Riverlands, & Braavos all behave. The position of Prince of the Vale is hereditary (confirmation of the Heir is done the same way as for the Archon, save that in the event of no confirmed Heir the title passes to the eldest dragon riding descendant of the last Prince unless a majority vote of dragon riders refuses them the position, and then down the list of claimants until one gets a majority); holding the position of Prince of the Vale (or being the confirmed heir to the title or the spouse of either) forever bars the holder from being in contention for becoming Archon and being Archon (or confirmed heir to that title) bars the holder from being in the running for Prince of the Vale.
3) Highgarden is located on the North side of the Mander and when the Tyrells surrender, they aren't named the Lords of an intacted reach. Instead, everything south of the Mander/Blueburn (up to the Kingswood) is seized and held in trust by the crown for a direct descendant of Aegon & Rhaenys to rule over as Prince of Summer (on the same conditions as the Prince of the Vale for passing on the title). When Dorne is eventually conquered, it becomes part of this domain. The Tyrells are given Highgarden as their seat and rule over the remainder of the Reach. While the Conquest of Dorne proper doesn't occur in this generation, the dragons do seize the mountains and the site of Vulture's Roost is chosen to build the Prince of Summer's seat (renamed Dragons Roost).
The biggest reason for breaking the Reach is to separate off Oldtown. The Dragons don't trust the Faith or Maesters and refuse to allow the Citadel or Starry Sept to exist in the territory of a Lord Paramount outside their control.
4) Royal titles (Archon, Lord of Dragonstone, Prince of the Vale, Prince of Summer, Prince of Winter, Prince of Iron) cannot be combined. To hold one (or be the spouse or confirmed heir or confirmed heir's spouse) forever bars the holder from being in the succession to any of the other royal titles.
5) The Prince of Winter is Warden of the North, Prince of Summer is Warden of the South, Prince of the Vale is Warden of the East, Prince of Iron is Warden of the West. The Warden of X is the third ranking military official inside their domain (only the Archon and Archon's confirmed Heir outranks a warden inside their domain) and enjoys the power of high, middle, & low justice over everyone within their domain. Outside of their areas of responsibility the Wardens still outrank everyone save that areas Warden but don't gain judicial power (or power of summary execution) over anyone save those from their own domains. So, for example, the Warden of the North could execute any nobel sworn to them (or anyone bound to said nobel) regardless of geographic location. They could also execute anyone (a few caveats apply) inside the territory that they hold primacy over regardless of who they are sworn to. All dragonriders and those acknowledged as Targaryen are forever outside the jurisdiction of a non Targaryen; only the Archon may exercise High Justice over a Targaryen and any Targaryen may appeal even the Archons judgement to the Conclave of the Dragon (the name for the body made up of all currently living dragon riders age 16 or over), where a majority vote can override the Archon's judgement); middle and low justice can be exercised by a Targaryen who would normally have jurisdiction over the individual.
The personal retainers & forces of a royal house are outside the jurisdiction of any save their own Prince/Princess and the Archon.
6) The raising of armed forces is restricted. Wardens can raise forces of unlimited size. Noble Houses can have up to a thousand armed retainers as a general rule (some are allowed more upon a petition by the relevant Warden to the Archon and the Archons approval), but Wardens can further restrict this number if they desire. A Targaryen who isn't otherwise empowered to raise personal forces can have up to a thousand armed retainers. The Archon can raise unlimited numbers. Everyone can have up to ten armed retainers. Merchants, foreigners, etc. can petition the Archon or a Warden to have more than ten armed retainers.
The Imperial Guard is raised by the Archon and is the Throne's personal force. By law, membership is forbidden to any acknowledged noble (bastards are fine, but no one in line of succession to any noble title need apply). The officer class is generally drawn from the commoners on Dragonstone (although exceptional outsiders can be raised from the NCO ranks to officer rank) while the rank & file comes from all walks of small-folk life. NCO rank requires the individual be literate, otherwise anyone between the ages of 16 and 25 can join (assuming that they can pass the physical exam). Service is a twenty year hitch of active duty with the ability to reup for another ten years and then another ten or twenty years of reserve status. Payment is three square meals a day, a decent salary (two silver per week, three in any week that they see combat, and twenty dragons upon retirement), and basic necessities (uniform, boots, living space in barracks, etc.). The Imperial Guard is primarily a pike & bow force although it also has light cavalry and a scouting force.
7) The Dragon Bank is established (and headquartered on) Dragonstone and is the official bank of Westeros. It is the only entity authorized to coin money (even the Archon is barred from doing so). It has a branch in King's Landing that, for anyone but Targaryens, is effectively its headquarters. It also has branches in the various capital cities/keeps. While some amount of gold is kept on hand for day to day affairs (and can generally be transported rapidly via dragon), the primary vaults are on Dragonstone. All taxes owed to the Throne must, officially, be paid in coin (in kind payments are not accepted) or direct transfer from one Dragon Bank account to another. All Noble houses (along with chartered businesses) must pay two taxes; one to the Throne and another to their liege. Payment to the Throne may be made at any Dragon Bank branch, tax payments to the liege are however said liege decrees.
Only the Dragon Bank is authorized to loan large sums (more than a hundred dragons), and taking a loan from a foreign entity is considered Treason if done by a noble. Loans may either be direct from the bank (someone visits the bank and applies for a loan) or sanctioned by the bank (the debtor and creditor visit the bank, pay the relevant fee, and draw up the loan conditions with the bank as witness and guarantor of the agreement; the bank is also the collection agent).
Finger prints are used to sign documents.
The Dragon Bank also acts as factor for a nominal fee. Anyone with an account may make an offer to buy whatever good or service on whatever terms, escrow the required funds, and then the request will be transmitted to all branches of the bank (or other interested parties). Then someone can choose to fill the order or not. The degree to which the bank acts in this role is dependent upon the terms of the offer and how much the parties are willing to pay. The cheapest option is essentially a classified ad; for the price of a silver you buy/sell advert gets added to the "book" and is posted in all bank branches for anyone to view, if someone expresses interest then you are notified and the banks role is done (advertisements remain listed for two hundred days per payment or until fulfilled or removed). The next level up is a buy request with the funds escrowed with the Bank; this is a slightly larger fee but lets any sellers know that the buyer is legit and has the money to pay for their order - the bank will act as notary and transmission agent for any written negotiations between the parties but otherwise doesn't play a role in the process. The next level up is the bank acting as a buyers agent; the funds are escrowed with the bank and the bank agrees to handle product inspection & delivery. The most expensive option is the bank acting as the seller's agent (especially if the goods being sold are perishable).
8) Aleyx brings technology with him. The most relevant parts are electricity generators. Attempts to reproduce Valyrian Steel result in his discovering that adding dragon blood to liquid metals and then letting it cool results in a metal that simply won't melt outside of direct dragon fire but otherwise doesn't appear to change its properties. Dipping dragon blood treated copper wire into liquid obsidian (dragon glass melted via dragonfire) mixed with dragon blood and letting it set results in an electrically insulated wire that retains its ductility. Wrap insulated copper wire around a steel (or iron) pipe, spin magnets inside the pipe, and you get electricity (which can be used to make stronger magnets for a more efficient translation of work into electricity). Electricity allows the production of chlorine gas (via the electrolysis of seawater), and reacting that with lime gets you chlorine powder (dissolved in water to make bleach). It also allows the production of magnets and thus cheap compass production.
Dragonfire also allows easy glass production. Mix dragonblood with a sheet of metal (so that it won't melt regardless of heat), use dragonfire to liquify sand (that then falls onto the dragonblood protected metal), ensure that the liquid sand is evenly spread over the protected metal, and wait for it to cool; the result is a sheet of glass (although even cooling is a must if you don't want it to crack). Mixing the sand with crushed dragon bone and some dragon blood results in glass that is far tougher than would otherwise be expected (not unbreakable, but it takes a strong man with a decent sledgehammer to harm it once it has cooled).
The secret of Valyrian steel is eventually found. Mix dragon blood, dragon bone, and dragon glass in a container protected against heat; the creator then cuts their hands and sticks them into the liquid substance, a dragon then breathes fire on the creator, the heat of the flame is transmitted by the blood into the mixture (which eventually turns liquid). Once the substance is liquid the creator shapes the liquid into the form they desire via their thoughts (a clear picture of the desired end goal is a must), when they feel the object is complete they quench it in the hearts blood of a human immediately after cutting off the dragonflame (this last step can be a bit of a pain if the object isn't pointy enough to properly stab someone in the heart). The objects form is then generally fixed (only the hottest fires, a master smith, and a great deal of dead bodies for blood magic rituals can allow it to be altered; and even then the end product is crude in comparison to proper works). What makes Valyrian Steel blades so absurdly valuable is that they are essentially molecular blades (being formed via thought, the edge is the sharpest of all possible things) that are immune to any change in their physical form regardless of the level of force employed (so smashing one against, say, granite won't do anything to the blade). This allows Valyrian Steel blades to be basically paper thin (thinner actually, from the side they are basically invisible) and thus be essentially weightless. The only thing that they can't slice through is Valyrian Steel; anything else they will cut with essentially the same ease as you could swing a regular sword through the air. Valyrian Steel armor is much the same, since it can't be penetrated or deformed regardless of the weapon used it can be basically paper thin without any issue. Chain mail using the finest of links (remember, formed by thoughts so basically perfect craftsmanship) inside of dragon skin leathers was the norm in the freehold (as it allowed peerless armor that was essentially invisible), although more ornate forms were used for combat (generally scale armor, designed to evoke the image of dragon scales, over chain and backed by padding). Plate was seen as pointless given how it restricted movement without materially improving protection. Even dragonfire won't melt Valyrian steel (although dunking it in dragonsblood heated by dragonfire will reliquify the Valyrian steel).
Electrical generation and insulated copper wire allow the production of a telegraph.
Powdered obsidian mixed with bone ash and slaked with a mixture of water & dragon blood results in a cement that will set in air over a period of a day or so (at normal temperatures). Once set, curing it via dragonfire results in Valyrian Stone (the substance that the black roads, the black wall, Dragonstone, etc. are built frome). The resulting stone is incredibly resilient and has a fixed temperature (around seventy fahrenheit) regardless of what is done to it (it also disrupts Others/White Walkers and the dead they raise). The Imperial Roads are built out of it, and inlaid inside the road are the telegraph wires. Dragonfire can liquify Valyrian Stone if the flame is sustained for any real length of time; this destroys its temper and results in worthless slag.
9) Those with the Blood of the Dragon are revitalized when exposed to dragon flame. A dragon breathing on them will cause wounds to close (and heal without scars, although not to the point of limb or organ regeneration), purify them of poisons, and burn out virtually all sicknesses. It also energizes them (and temporarily makes them both horny as all fuck & amplifies their emotions). Daily dragonflame baths while pregnant is what prevents the issues arising from incest (assuming that the babe is of sufficiently pure blood of the dragon to be fire-proof). This is also what mitigates against having a male Targaryen take someone not of the dragonblood as the mother of their children (as regardless of the babe, the mother can't survive the dragon fire cleansing); a female Targaryen taking an outsider as the father will never result in a child without the dragon blood as anything else will be aborted the first time they take a dragonfire bath.
10) The Eyes are the Targaryen spy network. They are overseen by the Lord of Dragonstone (the true spymaster) and knowledge of their existence is forbidden to anyone who isn't a dragonrider. The official (publicly known) intelligence service is whatever the Master of Whispers of the day is running and while that one may or may not be effective, it largely exists as cover for the eyes. The Targaryens make it a point to ensure that a Dragonrider involved with the Eyes is made Master of Whispers on a regular basis so as to ensure that the Whispers remain under control.
11) An Heir of a Noble House (regardless of rank) is only confirmed as such upon being presented to the Archon by the current holder of the title and, in the Archons presence, naming the individual as the Heir (they can also name an entire line of succession so long as all named successors are present at the ceremony). An Heir who is under the age of sixteen also needs a reagent, and the Regent must again be nominated before the court and confirmed by the Archon (the titles holder can name an entire succession list of potential Regents and have them confirmed as such). Absent a confirmed heir, the Warden who the title holds fealty to may choose anyone with a direct bloodclaim to the title (generally seen as children, grandchildren, or siblings of the previous holder). Absent a confirmed Regent the Warden may name anyone that choose to that position (although an individual with a legitimate interest in the title may dispute this to the Archon).
The Throne officially disavows any gender based preference for inheritance. Legal preference goes named & confirmed heir (for non nobles, this confirmation can be done by the Dragon Bank for a nominal fee), children under the age of 65 from oldest to youngest, grandchildren under the age of 65 from oldest to youngest, siblings under the age of 65 from oldest to youngest, children, grandchildren, siblings, anyone else with a blood claim with preference based on distance from the titles last holder. In the case of noble titles, that succession scheme is optional after confirmed heirs as the relevant warden can name any direct descendant or sibling of the titles last holder to the title (although they generally follow the succession scheme). In the case of non-nobles, that scheme is what is followed with the additional proviso that some crimes carry with them an inability to inherit as a penalty. In the absence of an identifiable & legitimate heir the estate reverts to the Warden (in the case of noble titles that owe a warden fealty) or the Archon (all other cases).
Adoption into a noble family may be done upon petition to the relevant Warden or the Archon by the head of the noble family in question (and agreement of the adoptee as well). In the case of a minor who is adjudged too young to consent, the adoption is provisional until the child reaches the age of 16 and goes to the Warden (or Archon) to either confirm or reject the adoption. This is also how basterds are legitimated (the only other method is via Archon's decree and that is virtually never done).
12) Officially, freedom of religion exists and religious toleration is required in the oath of fealty that all nobles take upon ascending to their throne. Taking religious vows bars one from ever holding noble title. Non nobles can be married by religious figures if the individual in question applies for (and receives) permission to performing binding marriages at the Dragon Bank and fills out the appropriate marriage certificates (which require the fingerprints of the bride, groom, and approved religious figure; extra witnesses known to the Bank are also preferred but not required). For a noble marriage to be binding, three officials of the Bank must also witness it. A marriage between someone thirteen to sixteen also requires the parents to apply their mark as witnesses.
A weirwood or sept may not be destroyed without the permission of a Warden or the Archon (in practice, any dragon rider could also get away with it).
Taxes may not be spent on religious services or infrastructure. There is something of an exception in this in that a noble can transfer funds from their titles account to their personal account and then donate the money if they want.
Those legally condemned to death can be executed before a weirwood (technically they can be executed anywhere the relevant authority damn well decides to have them executed).
Les Majesty exists and applies to everyone, even religious officials, but it only applies with regards to the Dragon Blood. Bitching about the local noble from the pulpit isn't a legally punishable offense (although the local noble may still illegally punish the speaker for it) but anything that can be construed as bitching about the Targaryens is a death penalty offense regardless of who is doing the bitching (although in reality it takes exceptional circumstances to get the death penalty).
Cremation is generally mandated for all deaths. The dragon riders make it a point to ride around on a regular basis and burn the bodies. This is primarily done to get bone ash for producing Valyrian Stone.
13) The vast majority of Valyrian magic is blood magic, they just tend to supercharge it via dragonblood. The usual method is to personally create an athame out of Valyrian steel and when creating it keep the exact magic that you want to achieve in mind. Then feed a victim a mixture of your blood and dragons blood before stabbing the victim through the heart; the victims life is then used to power the spell (if one life isn't enough then the charge can be stored for a relatively short amount of time inside the athame until enough people are killed to provide the needed power).
More generally useful is to enchant an object. Valyrian steel is generally the best material to use but other things also work (and some magics simply can't be enchanted into valyrian steel thanks to the inherent fire magic of the substance). The issue with enchanted objects is that they need a power source. The easiest source is to draw the power from the lifeforce of the user (a ring that burns out any poison the wearer ingests might age the wearer a month everytime it activates and an hour for every day that it is worn), but this tends to put a hard ceiling on how powerful the effect can be and shortens the users life. The next easiest is to permanently link an object to another living creature and have them power it - if linked to a human then the lifespan of the enchantment and its absolute power isn't increased, all that changes is who pays the cost; linking the enchantment to a dragon allows a much longer duration and a far greater level of power but it also makes a dragon mortal (dragons normally have no maximum life span, living until they become so large that they starve to death).
Next easiest is to link an object to something else that will draw the power (the freehold liked slave collars, as once one slave was used up the collar could just be put on a new slave to use them as the next battery). This can involve multiple power feeds for one enchantment (say a thousand slave collars all drawing at the same time to power one spell).
The hardest method is to draw power from the environment. The Freehold used great Valyrian steel plinths that were themselves powered by dragons (initially) and countless slaves (later) to in turn draw power from the Fourteen Flames and distribute that power out to all manner of other objects (the fall of the freehold was caused by a great many slaves being killed which destabilized the power taps which destabilized the volcanoes and caused them to all erupt at the same time while simultaneously causing everything linked to them as a power source to stop working). The Children of the Forest used the Weirwoods to achieve the same end.
Valyrian combat magic was basically pyromancy. They would create special foci (usually rings, but the real hardcore would replace a bone with a Valyrian steel replica) that would channel the fire through their bodies and let them control it. Needless to say, this was lethal to anyone who wasn't immune to fire/heat. Powered by the Fourteen Flames, this allowed those of the Freehold to cast staggeringly powerful fire magic (think Avatar levels with Sozin's Comet in the sky) at essentially no cost or effort. Post Doom, only linking to a dragon would allow anything approaching that level.
The enchantments on Dragonstone were linked to the dragons that Aenar brought with him (and when the Black Dread dies those enchantments fall).
The most effective enchantments tend to be the ones designed to stop an unauthorized individual from touching/using an item. This is because once they are initially primed they do nothing when someone authorized (generally only via blood) touches them and thus use no power, whenever someone not authorized touches them they use that individuals own lifeforce to burn said individual to ash and recharge the sensing magic. Given long enough (a few centuries) the sensing magic will wear off and the item will essentially become inert, but otherwise the whole thing is self powering. This was a very common enchantment on Valyrian Steel objects (if you weren't of the Blood then touching them was death).
Enchanted items of note:
-The "Painted Table", Aleyx and Visyena used a blood sacrifice to cut down a weirwood tree but keep it still living, carved it into a flat plane, impregnated it with dragon blood, and encased it in enchanted dragon glass (remains charged by putting someone without the Blood in the throne every so often). The purpose is to keep the weirwood linked to its brethren and so use the weirwoods as spies of a sort. The glass takes the information and uses it to display a real time holographic projection of the land of Westeros (although it is less detailed the further away from a weirwood a location is). Linked tokens also allow the tokens current location to be displayed. While the table doesn't generally show people (they are simply too transient for the Weirwoods to notice), it does provide an accurate geographic map of Westeros that is to scale.
-Glass Candles. Created via the ritual sacrifice of actual prophets, they allow the user to see possible futures and distant locations (and thus communicate with one another as well). Notoriously unreliable as it turns out that most people don't want to have their souls bound to an object to act as someone elses crystal ball for the rest of eternity and so they generally try to actively ensure the death of anyone who uses them.
- Farsight Mirror. Created by Aleyx & Visenya, a mirror is made of Dragon Glass over Valyrian Steel and a linked dagger. When charged (via stabbing someone with the dagger), the mirror displays what the dragon whose blood was used to make it currently sees and (if the user is that dragons bonded rider and said user puts their bleeding hand on the mirror) allows the user to communicate with the dragon.
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Plot wise, the addition of Aleyx and his marriage to Visyena removes Maegor from consideration (his equivalent would be the acknowledged heir of the Vale and thus out of consideration for the Throne) while the war with the Faith and securing their conquests keeps the First Dornish War from ever being a full blown thing and thus Rhaenys is never killed (and so has more children). Her, Visenya, and Aleyx also regularly rotate through Dragonstone (Aegon is less common but he still visits a great deal) and raise the groups children. Aleyx argues (successfully) that with the hostile Faith and a restive (newly conquered) populace it simply isn't safe to raise their children in either Kings Landing or the Vale, that they can't raise them separately as House Targaryen can't risk anything less than unity in the next generation (any kind of disunity among the family simply being too dangerous given their low numbers), and that they can't risk them being corrupted by the locals.
Aegon's second child is a daughter, in the vein of Visenya for temperment, and she ends up wedded to Aleyx's third child (his eldest son is wed to a Velaryon) and becomes the first Princess of Summer.
The Faith war eventually ends with the cutting of a deal. After twenty five or so years of the Targaryens burning any nobles or septons who were too open in their resistance, standing bounties on the members of the Faith Militant, and simple slaughter of any large bodies of forces (using Northern Wargs with birds of prey for surveillance) that are fielded the Targaryens finally offer the Most Devout and their biggest backers a deal. They can bend the knee, disband (and forever renounce) the Faith Militant/Poor Fellows, and accept the primacy of the Throne and Aegon will amnesty the lot of them or they can refuse and the gloves will come off. Aegon will instead declare all Septons and Septas to be anathema and make providing aid or comfort to them a death sentence, the dragons will them proceed to go from population center to population center and tell the populace that they have one day to provide the heads of all Septons and Septas in their city/town/village or the dragons will put the entire place to dragon flame. The same will happen to any city/town/village that has been given the ultimatum and in future allows a Septon/Septa to reside within their walls for more than a day. He flatly tells the Most Devout that they can either bend the knee or the Dragons will give up on a nice war and resort to basically genocide against the Andals.
The Faith agrees to accept Aegon's terms. In large part because they aren't actually winning the hearts & minds battle. It is Targaryen forces that have been patrolling the roads, providing food to the hungry, offering jobs, bringing peace, and reducing their taxes. With their dragons they simply don't see any reason to raise large armies of conscripts and they force the nobles to behave (and not war with one another). The Targaryen's also spend a great deal of money on propaganda.
The biggest source of funding is glass production, largely exported to the free cities. Myr is informed that they can either accept it or the alternative is that the Dragons pay a visit and simply burn the competition to the ground. This allows them to get by with relatively small tax rates.
The other big source is their trading fleet. Aleyx knows about copper sheathing ships (using nails made from dragonblood treated iron and insulated via dragon blood treated obsidian protects them from the dissimilar metals issues). He also knows about steam engines. Thanks to dragon fire it is really easy to make high quality steel. Valyrian Steel allows for extremely high pressure bottles as well while dragon powered steam engines (and their sheer strength) allow for extreme compression; the end result is that steam engines on the ships are powered by hydrogen gas.
There are also blimps. Valyrian Steel allows you to create a vacuum chamber that will retain its form despite being thinner (and lighter) than paper. You make the vessel just slightly less than neutrally buoyant and then have another chamber that you pump air into or out of to fine tune the load.
Railroads as well. With the tracks laid as part of the Imperial Roads and the trains powered by steam engines (making a reliable ignition system for an ICE is a bit of a bitch)
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My second idea was an SI as the younger brother (again by about two years) of Rhaegar, this time with knowledge of the show/books. Or maybe a Viserys SI. That would be a bit more interesting.
So thoughts?
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