Angel, Pelagic Deva

Amphibious. Can breathe air and water.

Angelic Weapons. Its weapon attacks are magical. When it hits with any weapon deals extra 4d8 radiant (included below).

Immortal Nature. Doesn't require food drink or sleep

Living Coral Armor. Its armor is made of living coral. If armor is damaged such as from a black pudding's Pseudopod armor fully repairs itself within 1 min provided it wasn't destroyed.

Magic Resistance. Advantage: spell/magic effect saves.

Multiattack. Three Trident attacks.

Trident. Melee or Ranged Weapon Attack: +8 to hit 5 ft. or range 20/60' one target 7 (1d6+4) piercing damage + 18 (4d8) radiant. If deva makes a ranged attack with its trident trident returns to its hands at start of its next turn.

Transforming Touch (5/Day). Can magically polymorph a willing creature into a giant octopus hunter shark or plesiosaurus. Transformation lasts 8 hrs until target uses a bonus action to transform back into its true form or until target dies. Items target is wearing/carrying are absorbed into new form. In new form target retains its alignment and Int Wis and Cha scores as well as its ability to speak. Its other stats are replaced by those of its new form and it gains any capabilities that new form has but it lacks.

Anoxic Aura (1/Day). Removes oxygen from nearby water for 1 min. Each creature that requires oxygen to live (including air-breathing creatures under effects of water breathing) and starts its turn within 20' of deva: DC 17 Con save or begin suffocating. Deva never suffers effects of this; can choose any creatures in area to ignore it.