is the seventh stage in Sub-chapter 25, Scars of War
Using stackable attackers is good here to take out the Gory Blacks. Once the field is clear, send out A. Bahamut to deal huge damage to the Sunfish Jones. Repeat this until the sunfish is dead.
Bringing Bombercat helps a lot, as well as Dark Lazer to quickly take out gory blacks. The rest is the same as 1/2/3 star. Send A. Bahamut if the field is clear, repeat until the fish is dead.