The Lurker Below

The Lurker Below is a subclass that has gained water based attributes from a revival by an entity from the deep ocean. This can be the same patrons a a Fathomless Warlock, Ocean deity's, or another powerful water based being. 

Reborn from the Depths

Starting at 3rd level, you no longer require to eat, drink, or breath, as your body is a drowned husk. You also gain a swimming speed equal to your walking speed. 

Drowned Man's List

When you choose this archetype at 3rd level, you gain access to your Drowned Man's List. This is your list of targets, and its appearance is dictated by you. As a bonus action, you can choose a creature you see and write them down on your list. When a creature is apart of your list, you get additional ways to use your sneak attack against that target: you do not need advantage on your attack roll If you are within 5 feet of the target, and do not have disadvantage on the attack roll. All other rules for sneak attack still apply to you. If a creature is reduced to 0 hit points, its name is magically removed from the list requiring no action. You can remove any number of creatures from the list at the end of a long rest. You can have a number of creatures on your list equal to your proficiency modifier. 

In addition, at the start of your turn, if creature on your list moved on its last turn, and is within 30 feet of you, you may teleport to an empty space within 5 feet of it. You can only do this once per creature. 

Lurker's March

Due to your connection to the waters, they embrace you and allow you to hide amongst the tides. While submerged in water or in heavy rain, you can use a bonus action to turn invisible until you move, use an action, or use a reaction. 

In addition, after teleporting using your drowned mans list feature, you become invisible until the start of your next turn.  

Hook, Line, and Skewer

From the 13th level, you can summon a spectral skewer to reel in your next catch. As an action on your turn, you may summon a spectral skewer, and aim it at a creature within 90 feet. Make a ranged attack roll against the creature. If you hit, you deal 3d6+ your Sneak Attack as magical piercing damage, and you may reel the creature 30 feet in a straight line towards you. If you are submerged while using this feature, you may reel the creature up to 90 feet instead. 

You can do this a number of times equal to your proficiency bonus per long rest

Sleep with the Fishes

Starting at 17th level, you can uses turn the oceanic forces that have doomed you onto your enemies. As a bonus action, you can create an aquatic sphere centered on yourself. For the next minute, each creature within a 15 foot radius of you, as well as yourself, is considered submerged. While using this feature, you can grant a 30 foot swim speed to any creatures of your choice in the area. Additionally, any creatures of you choose that start their turn in the radius have their names added to your Drowned Man's List. 

If underwater, the sphere is considered heavily obscured instead, as the waters darkened. You and any creatures of your choice can see through the sphere. 

You can use this ability once per long or short rest.