The Pit; Bloody Pleasure of the Undercroft.

[SakikoMiley]

Rank 0: "Pansy" Key Fights
7 Corrupt Bunnies
Tim
5 Hoplites

Rank 1: "Pit Dog" Key Fights
3 Nymph
2 Werewolves
Granite Golem

Rank 2: "Bloodletter" Key Fights
3 Black Recluse
2 Pigron
Bone Lee

Rank 3: "Gladiator" Key Fights
The 3 Haunted Weapons (Sword, Hammer, and Axe)
Evolution Beast
(Undetermined)

Rank 4: "Executioner" Key Fights
Stargazer
Vortexian
Predictor
Selenian

Rank 5: "Blood Brother/Sister" Key Fights
Ice Golem
2 Hellhounds
(Undetermined)

Championship:
Juri Bahn with a Royal Gel, and 2 Gastropods, 3 Illuminant Slimes, and 5 Corrupt Slimes.