Complex sentence: He recruits Akumi and the Warumo Gang to help him break free from his seal and defeat Mirumo and his friends; while on the verge of breaking free, Mirumo and his team enter his world and defeat him.
Split into simpler sentences: He recruits Akumi and the Warumo Gang to help him break free from his seal and defeat Mirumo and his friends. While on the verge of breaking free, Mirumo and his team enter his world and defeat him.