Square Enix has a game about becoming King Arthur and uniting Britain to protect itself from invaders. The catch is that it’s a card battling game that is also filled with lots of anime girls. I’ll have to warn you, the below video showing off the recently released DLC that adds swimsuits and jiggling is a bit much.
The game was originally released for mobile devices. The Vita version has a lot of improvements like full voice acting, rebalanced gameplay, improved visuals and the ability to edit your deck. The full name of the game is Kaku-San-Sei Million Arthur. It’s free to play if you have a Japanese account on Vita.