Wrath of Hell is the 1st stage of The Great Diablo. Next stage: Wrath of Hell (Merciless).
Aku Cyclone's Shield blocks status effects, so it is brute force or a Shield Piercer (Lilin, a Talented Li'l Macho Legs) — either way the fight is stackable DPS grinding it down.
- Can Can, Cameraman and Pizza Cat are the DPS stack; Eraser and Manic Eraser are the walls.
- Bellydance Cat with the Target Aku Talent works because the stage is only Red and Aku; Brainwashed Cat dodges Aku attacks and is disposable, but Ginger Snaches trouble it.
- The Little Warriors combo gives you Cameraman and Li'l Eraser plus an easy Unit Defense Up; add a small Defense combo like Sportswoman for the meatshields.
Aku Cyclone moves slowly and deals relatively low damage per hit for a Cyclone, but more than makes up for it with a 1,666,666 HP Shield that regenerates with 100% HP each time it gets knocked back. Since it has 1,666,666 HP itself and gets knocked back 4 times, this effectively quintuples its health if you don't have any Shield Piercing Cats.
LI'L MACHO LEGS CAT B Due to its shield blocking status effects, you must either use brute force to destroy Aku Cyclone or use Shield Piercers, such as Lilin or Talented Li'l Macho Legs. 
CAMERAMAN CAT B Regardless, the main strategy is to use stackable DPS units such as Can Can Cat, Cameraman Cat and Pizza Cat and gradually whittle it down. 
CAN CAN CAT A Regardless, the main strategy is to use stackable DPS units such as Can Can Cat, Cameraman Cat and Pizza Cat and gradually whittle it down. 
PIZZA CAT A Regardless, the main strategy is to use stackable DPS units such as Can Can Cat, Cameraman Cat and Pizza Cat and gradually whittle it down. 
MANIC ERASER CAT S For stalling, Eraser Cat and Manic Eraser Cat are your best choice. 
ERASER CAT S For stalling, Eraser Cat and Manic Eraser Cat are your best choice. 
BELLYDANCE CAT A If you happen to have unlocked Bellydance Cat and her target Aku Talent, she can work as well, since the stage features exclusively Red and Aku enemies. 
BRAINWASHED CAT B Brainwashed Cat is also good to have, as it can dodge attacks from Aku enemies and is disposable, though it might struggle if the nasty Ginger Snaches get in the way. ⚙ More counters worked out from the roster, lower confidence than the picks above; kept for reference
Aku Cyclone is Aku. Anti-Aku units take less damage and deal more.
MASTER URIL A Esoteric Uril: Strong against Relic, Aku (Deals 1.5x damage, only takes 1/2 damage) Also fits “Out-range Aku Cyclone.” 
PAPERBOY CAT A Insane damage to Aku, and immune to Surge — the Aku Realm's signature threat. Also fits “Out-range Aku Cyclone.” 
NYMPH CAT A True Form knocks back Aku enemies. Also fits “Out-range Aku Cyclone.” 
HEAVENLY GOD SUPER ZEUS S Slows and resists Aku enemies. Also fits “Out-range Aku Cyclone.” 
CAT CACTUS B Cat Cactus: Strong against Aku enemies (Deals 1.5x damage, only takes 1/2 damage) Aku Cyclone reaches 200 range. Units that out-range it can chip safely without taking hits.
GROSS CAT A Range 350 — fires from beyond its 200. MASTER URIL A Range 405 — fires from beyond its 200. Also fits “Counter Aku.” 
PIED PIPER CAT A Range 320 — fires from beyond its 200. Also fits “Counter Aku.” NYMPH CAT A Range 300 — fires from beyond its 200. Also fits “Counter Aku.” 
CHILD OF DESTINY PHONO S Range 600 — fires from beyond its 200. Also fits “Burst the boss down.” Aku Cyclone has a deep HP pool (1,666,666+ even before stage magnification). Heavy single-target burst shortens the fight.
BAHAMUT CAT S Huge multi-hit burst — a story-unlock powerhouse that deletes tanky enemies. 
MIGHTY REKON KORPS S Among the highest single-hit Area damage available. Also fits “Out-range Aku Cyclone.” 
GAIA THE CREATOR S Long-Distance multi-hit with Insane Damage — a generalist wall-cracker. Also fits “Out-range Aku Cyclone.” 
CRAZED MONEKO A Big crit burst against tanky/Metal targets. 
TECOLUGA S A 7,300-AP long-range hit obliterates tanky targets when the Critical connects. Also fits “Out-range Aku Cyclone.” 
The castle you destroy to clear the stage.