A deep one priest can breathe air or water with equal ease.

On its next turn after a deep one hybrid priest takes 10 or more damage from a single attack, it has advantage on its melee attacks and adds +4 to spell and claws damage.

A deep one hybrid priest is immune to the pressure effects of the deep ocean.

A deep one born to a human family resembles a human child, but transforms into an adult deep one between the ages of 16 and 30.

A deep one priest may sway an audience of listeners with its rolling, droning speech, fascinating them for 5 minutes and making them dismiss or forget what they’ve seen recently unless they make a successful DC 13 Wisdom saving throw at the end of that period. If the saving throw succeeds, they remember whatever events the deep one sought to erase.