Echizen (越前 Echizen) is a super sadistic crab. He has known Wakasa since he was young, and is seen trying to take Wakasa back to the ocean on several different occasions.
He used to be best friends with Takasu too, until they met a much older Wakasa and they began to fight over him until they were no longer friends. Wakasa was oblivious to this conflict. Echi actually wants to be friends with Takasu again.