Casual mode should return only so you can save right in the middle of battle, the returning of a unit after it has died should be abolished as its not real fire emblem unless a unit dies permanently (until you find an aum staff).
Just got kingdom hearts 2.5 HD remix and starting off with birth by sleep, first time playing a KH game and I havent got a clue on how to fight on here , so starting the game on aquas story ☆彡