Labyrinth of Hades is the last stage in Parthenon.
Kory appears as a major threat to your cats.
Bun Bun Black appears as a boss.
Spam meatshields and long-range wave attackers such as Crazed Sexy Legs Cat.
The Kory is a major threat. Basically, if it was only Kory you could just spam long-rangers. However, if you do that, Bun Bun Black will just kill them quickly. So you will need to use meatshields, 2 is recommended. The rest should be filled with long rangers such as Paris Cat.
Don't bring any units if their Health/Knockback is lower than 2800 (5600 for a close ranger) because 2800 is the damage of Kory's waves.
Bring at least one anti-floating/anti-black character for Bun Bun Black, though not knockback, slow, or freeze. While they can stall Bun Bun Black for a few moments, Kory will be able to shockwave much more easily.
Once Bun Bun Black is knocked back, this is a golden opportunity for you to attack Kory (he's knocked back once every 77,777 health).
You can avoid Kory's shockwaves by using weak meatshields so that when they're killed by Bun Bun Black, Kory will miss, and the attack wave won't form. For example, the true form of Tank Cat, Eraser Cat withstands a Bun Bun Black hit, being victim to Kory's waves, while his evolved form will die from Bun Bun Black's attacks, making Kory miss his target.
In any case, you'll need meatshields to protect your units from the Bun Bun Black.
Another strategy that I found is on this reddit link https://www.reddit.com/r/battlecats/comments/2xjzkg/help_on_labyrinth_of_hades/
For 4 star difficulty, this can be quite difficult as Bun-Bun and Kory will pretty much destroy your units with the 3.0 magnification. It is suggested to use the double research combo (Skelecat, Mr., Necromancer), along with Cameramen + Paris Stacking. Also, you could stack Necro-dancers along with Cameramen, and do perfect timing with A. Bahamut to kill Kory and Bun-Bun. Awakened Bahamut should be deployed just right before they sync in position.