Fish Devil

Fish Devil (魚の悪魔, Sakana no akuma) is the devil who embodies the fear of fishes.

Personality
Nothing is currently known about the Fish Devil's personality except it presumably possesses hatred for humans like all non-humanoid devils.

Plot
At some point, Fish Devil has eaten a chunk of the Gun Devil's flesh.

Eternity Devil arc
The Fish Devil was killed by Aki and Himeno, and the Gun Devil flesh fragment was recovered from its corpse.

Abilities
Contract Creation: As a devil, the Fish Devil can bestow contracts upon humans for a price.

Blood Consumption: As a devil, the Fish Devil should be able to restore its health by consuming blood.

Revival: As a devil, the Darkness Fish should revive in Hell after being killed effectively making it immortal.