this game is actually a pleasant surprise since there's only a handful of games about the Warring States era.
it's basically a combination of Crusader Kings and various elements from the Total War games, plus some of the devs own unique design choices, such as the fact that you can have harems (lol) and your generals can basically do their own thing if they're not loyal enough to you.
there is a prequel for this game, but the English translation for it is awful. the translation in this one is better, but it's still....... off: