In this AU you're one of creatures with human upper body, shark/octopus/squid/dolphin tail lower body.(you choose)

There's a male group in the deep layer. Two sharks, One squid and one black octopus. Killer, Dust(sharks), Error(squid), Horror(dolphin) and their boss Nightmare(octopus).

Dust was swimming around, exploring the reefs. Horror and Killer were fighting near the reef, while Nightmare was sitting in their cave, and Error was knitting something with algae’s.