Deep One
Medium Humanoid, chaotic evil
Armor Class 13 (natural armor)
Hit Points 91 (14d8+28)
Speed swim +30, walk +30
Challenge 2
Saving Throws cha +3, con +4, str +5
Damage Vulnerabilities fire
Damage Resistances cold
Senses darkvision 120 ft., passive Perception 9
Languages Common, Void Speech
Special Abilities
Amphibious. A deep one can breathe air or water with equal ease.
Frenzied Rage. On its next turn after a deep one takes 10 or more damage from a single attack, it has advantage on its claws attack and adds +2 to damage.
Lightless Depths. A deep one is immune to the pressure effects of the deep ocean.
Ocean Change. 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.
Actions
Claws. Melee Weapon Attack. +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) slashing damage.
Source: Tome of Beasts · OGL/Open