each character is supposed to have their own lore, but one of the best I read was that of Yamato (Microwars LATAM) It was literally the Yamato from the Japanese version of the game (ToyWars) that after a war against robots and losing everyone his friends, escape by boat or plane (I don't remember XD) to Latin America and meet the other characters to later realize that there is a zombie invasion (LOL)