Eris's effects aren't resetting each game. the round counter used for some of her cards would persist between games, putting it at max power from the start, and her reality warps would stay in effect even after Eris is no longer in play. in fact, the first time i changed characters after play Eris, i was still given the option to pick a reality warp. when Eris came up as an opponent, her last Reality warp (Wild Growth) persisted well past when i beat her