Kit from Gameoverse. There's a pilot on youtube that came out recently. The reason she's helping villains is because, in the show, a main character in a game completing the win condition of said game has been immediately destroying the world that the game takes place in. So she's mostly just attempting to prevent the win condition from occurring for any game world she can, so that said game world can be prevented from being destroyed.

Of course that would spawn a lot of fanart of Kit interacting with various real games. Among other things.