Ancestry of the Depths

You may have been having mysterious voices call out to you from the ocean's depths to hear the whispers get stronger and more compelling. Yet they call out to you not with malicious intent but with delight because of familiarity. Somewhere along your lineage a sea elf, hag, or deity of the waters entered your bloodline and their magical powers laid dormant until you came along. Now able to wield the might of the ocean and have dominion of the watery elements, you only scratch the surface of the magical capabilities that are present for one with ancestry from the deep.

Boon of The Depths

At 1st level gain the following abilities:

• Cutaneous Respiration: When underwater your skin allows you to breathe while submerged.
• Gain a swim speed of 60ft
• You are now resistant to cold damage (becomes immunity at 14th level)
• When surrounded by at least 5ft of magical water (created by you or not) gain a +2 to AC
• Gain shape water as a bonus cantrip
• gain access to spells from the warlock spell list.

Song of The Sirens

Starting at the 6th level, as a bonus action, turn to one creature you see and make them roll a Wisdom saving throw. On a fail, the creature will be incapacitated for 1 min while listening to the song and take 2d8 psychic damage at the end of each turn. The targeted creature is allowed to reroll the saving throw at the beginning of the turn to free themselves from the song. If the creature fails the saving throw by 5 of the DC add 2 additional d8s to the damage. 

This can be done a number of times equal to proficiency bonus.

Blessing of Aquarius

At the 14th Level, gain the following abilities:

• Immunity to cold damage.
• When surrounded by at least 5ft of magical water (created by you or not) gain an additional +3 to AC. (This is added to the plus 2 from "Boon of the Depths")

When magically affecting water through shape water you can do the following: 

• You can now control 60ft of water.
• The effects caused by this now last for 8 hours.
• If you freeze a section of water of any of the 60ft of water and a creature is present, They must succeed on a Strength saving throw or take 3d10 magical bludgeoning damage. On a success, they take no damage and are free, on a fail take full damage and roll the saving throw again to free themselves (STR DC 15).
• You can lay the water on the ground and cause it to become difficult terrain for enemies.

Mastery of The Deep: Harbinger

Beginning at 18th level, as an action gather your magic and strength to bathe yourself in Abyssal waters and take up the mantle of Harbinger for a full minute.

Harbinger of The Deep: While in this form gain the following abilities

• Immunity to grapple and restrained conditions
• Attacks or spells that deal cold damage bypass resistance 
• Movement speed and Swim speed increase by 30ft, and movement in this form do not provoke opportunity attacks.
• Once per turn add spells and attacks deal an additional die of cold damage

Abyssal Terrain: as an action envelop the earth before you causing the ground to change to what lies at the bottom of the ocean, these effects last for the duration of Harbinger of The Deep. Enemies within the terrain must roll a Constitution saving throw (DC equal to Spell DC) or feel the true pressure of the ocean. On fail, enemies take 6d10 force damage and become slowed (enemies must pick reaction, bonus action, or action and only get one. Also, they receive a -3 AC penalty under these effects.) On a success, they take half the damage and are not slowed. This can be reactivated up to 3 times while Harbinger of the Deep is active. (This gets a free activation, then 2 additional activations while Harbinger of The Deep is active) Any creature that this ability has slowed can reroll the save at the end of its turn.

This can be done once per long rest.