For this game I think a pokemon that steals unite moves and pokemon abilities would make the game a ton more unique and exciting. So I nominate Marshadow to be that playable pokemon because a pokemon of that type of caliber would be very fitting for a mythical pokemon. So my feedback would basically be adding Marshadow to be the definitive copy pokemon who steals buffs, unite moves and if it gets a K.O it can steal the form of the defeated pokemon.