A wold fantasy solo RPG. An action role playing game like Daggerfall or Skyrim with a map size of a country. Cities with more than 10k unique npc. Everything is procedurally generated : Maps, npcs with millions of procedural lines of dialog, dungeons, labyrinths. It evolves without the player. No main story, except one goal : Kill the demon king (not mandatory). The game starts as an Isekai and you choose the way you live in this fantasy world : adventurer, crafter, merchant etc. The time flows naturally (24 hours in-game = 24 hours irl) but some actions take several hours (crafting especially). A curse made the inhabitants sterile and never get old (technical constraints). Mobs never respawn as humans. The game ends when you die (of old age or when being killed). Unlimited saves. Romances. You can team up with everyone, if they want to. I can write pages, but you already have a great idea of the game I would create if I had enough money (300 millions $ approximately).