So recently, I've been watching a lot of shows that are set in fantasy settings and/or reincarnation is a major part of the plot, such as Overlord, That Time I got Reincarnated as a Slime, and Goblin Slayer. While reading a quest called "Fate: Conquest" by Spartacus (which you can find on this site in the IC Roleplay section), I got this idea for a possible fic. Now before I begin, please know that my knowledge I have about the extended Type-Moon universe is very limited and it mainly uses ideas from the Fate-verse.
In the not-to-distant future, VR technology makes giant leaps in development that ultimately result in the development of a system that can completely envelop its user in the game they play, similar to the VR systems you see in SAO and Overlord. As a result, VR gaming explodes in popularity and it quickly overshadows regular gaming as most companies begin to turn their efforts into creating new VR games. One game that comes out is known as (Game title still in development) that is set on a fantasy world where magic is common and contains many creatures that exist in a Type-Moon work one way or another. There are classes that are based on the various professions in the TM-verse (Magus, Church Executor, etc) and can either be chosen upon starting, obtain by advancing in a starting class, or earned by completing a certain objective or achievement. Perks are also present and vary from more mundane skills (crafting magical items, proficiency with a certain weapon type, etc) to the more magical powers (Mystic Eyes, proficiency in a certain school of Magecraft, etc). Like classes, perks can be earned by either leveling up or completing a certain objective.
The most powerful classes, however, can be taken by obtaining what is known as a Class Card, rare items that infuses the user with the power of a Heroic Spirit and grants them the abilities of said spirit. Class Cards themselves are rare as it is due to only one existing for each Heroic Spirit and the difficulty on obtaining one depends on the power of the Spirit (The Card for Hector would be easier to obtain than the Card for Achilles and so on). They are also dropped upon the death of the player and can be taken by their killer unless they are already using a Class Card.
Anyways, the story takes place a few months after the game is released, there are some fairly high-level players around and some people have already obtained Class Cards and dominate the ranks. One day though, each and every player finds themselves in the game, now their reality, and as their avatars. Panic ensues for a time before most come to accept that the game is now real and begin to rally around more powerful players, mainly those with Class Cards of powerful Heroic Spirits while those with weaker Class Cards ally themselves to those with stronger ones, minus some that operate independently. This eventually leads to the formation of new nations and governments that quickly seize land from any NPC, now living people, that owns it. These nations are mainly run by Class Card users, who are now starting to slowly inherit the personality traits of the Heroic Spirit, with the strongest of them being the main leader. Many Class Cards are still not taken however, the most powerful ones are still hidden somewhere in the world. The story begins to revolve around an independent band of adventurers that discover the Class Card of Scathach after raiding a dungeon based of Celtic legends. Meanwhile, tensions are brewing between the various nations and war seems to be on the horizon.
The ideas I had for nations so far would be:
The Second Roman Empire: The most powerful nation at the start. Militaristic and Expansionist, the 2nd Empire is a centralized state with a well-disciplined military. Dominated by users with the Class Cards of Roman emperors and generals, the Empire is always looking for an excuse to expand their realm and, with the current situation, they may just have it. The 2nd Empire is headed by the user with the Class Card of Romulus.
The State of the Church: A Theocracy only in name, the Church is ruled by a hierarchy of "Living Saints" and is headed by the user with the Class Card of Jeanne d'Arc. Respected by most of the other powers in the world, the Church usually acts as a mediator between two hostile nations and always tries to end things peacefully, but with current tensions, it's proving to be nearly impossible now.
The Carolingian Federation: Based on the Holy Roman Empire of old, the Federation was the first nation that was formed by players due to its more decentralized way of governing and granting regions outside the capital considerable autonomy. In recent times though, the Federation has been in an era of stagnation and decline and may find itself woefully unprepared if war were to erupt. The Federation is headed by the Class Cards users of Charlemagne and his Paladins.
The Realm of the Round Table: Also known as New Britain, the Realm is a nation of knights, chivalry, and faith, united by the once and future king!....If they were here that is. In truth, the Throne has been vacant for quite some time and has been ruled by a Regency Council that consists of members of the Round Table, with the actual Regent being someone with an unknown Class Card. The Realm proclaims that the only one who will sit on the Throne will be the one who finds the Class Card of the great King Arthur, though some feel that may be an excuse for the Regency to stay in power. Though it has the potential to be the most powerful nation in the world, it's fighting multiple wars against the armies of various "Pretenders to the Throne" AKA those who have Class Cards of alternate versions of their King (Lancers and Alters) that the Regency refuse to acknowledge as their liege.
The Empire of the Conqueror: The perfect description of an army with a state, the Empire of the Conqueror is a nation where each civilian is a soldier that fights against the world in an effort to conquer it, either by fighting on the frontlines or producing materials for the war effort. Considered a rogue state by all others, they are still a major threat to those who border it due to its policy of complete mobilization and the large number of Class Card users it has. As you may have guessed, it's headed by the one who has the Class Card of Iskandar.
The Army of Oblivion: Similar to the Empire of the Conqueror, the Army of Oblivion is a roaming force that pillages and destroys everything in its path. A bastion for necromancers (necromancy is banned in most nations) and those seen as criminals and monsters, the Army seeks to destroy the world and rule the ashes. The one who heads the Army is the Class Card user of Jeanne d'Arc Alter.
No-Man's Land: Not a nation officially, No-Man's Land is a mountainous region consisting of small villages and hamlets. While many other nations tried to invade the region, they found themselves stopped by the mountainous terrain and the guardians of the land: the 19 Hassans, who disrupts the invading forces through a combination of sabotaging their supply lines and assassinating the chain of command. While headed by the Old Man of the Mountain/King Hassan, he barely interferes in internal affairs and the Hassans rule in his name, independent of one another. They will always obey the first Hassan if he issues an order and they will do so faithfully, lest they risk their heads.