Pact of the damned seafarer

Your patron is a sailor or pirate who died at sea and whose corpse was left at the bottom of the ocean. When a ghost comes back to our world they are sometimes tied to the place they died, the only problem is a ship isn’t a place it’s a thing that moves. The place they died and the place where the ship they died on is, are two different places. Because of this people who died at sea become tied to the very ocean itself. So essentially your patron is the entire ocean… but it’s possessed by a ghost. Beings like this are vengeful and cruel. It is said that every storm that occurs on the sea is caused by them. Their wrath creates rough waters and deadly waves. If you make a pact with one, they might want revenge on whoever killed them. Or if no one killed them and they died of natural causes, they might be angry at no one in particular but they might just be angry in general and want you to help them lash out at the world. To do this, they give you powers related to death and the sea. Whether you use them to take your patrons revenge or not is up to you. Or should I say, weather you use them for that purpose or not (i’m not sorry at all).

Expanded Spell List

The Damned seafarer lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

damned seafarer Expanded Spells

• 1st: Bane, create or destroy water
• 2nd: misty step, invisibility
• 3rd: bestow curse, water breathing
• 4rd: control water, black tentacles
• 5th: hallow, arcane hand

Dweller in the deep

At 1st level you can enter a ghost-like spectral form while in water. While in water you become slightly translucent and turn a shade of muted blue-ish green. You gain a swim speed equal to your walking speed plus 10 (if you already have a swim speed that is faster than you walking speed, your swim speed becomes your current swim speed plus 10). While swimming, you can use an action to pass through one wall or object that is no thicker than 5 feet.

Curse of the black spot

At 6th level you can mark an enemy to be killed. As a bonus action, you can mark a creature within line of sight with a black blot somewhere on their skin that goes away after 30 minutes. While the blot is on their skin They have vulnerability to necrotic damage and whenever they take any damage, they also take 1d4 necrotic damage. Additionally, any undead with an intelligence of 6 or less that sees this creature will immediately become hostile towards them. This effect is considered a curse and thus can be removed with the remove curse spell. You can do this a number of times equal to your charisma modifier. At 10th and 14th level the time this effect lasts goes up by 30 minutes and at 20th level it increases by an hour. Also at 20th level, you can choose one creature to have this effect indefinitely or until someone cast remove curse on them or you choose to remove the curse (which can be done from any distance).

Summon drowned spirits

At 10th level you can call some of the less powerful spirits in the ocean to emerge from nearby water and fight for you. As a bonus action, you summon a Specter that emerges from any nearby water that is more than a foot in length and width, depth doesn’t mater. the Specter looks like a normal Specter except it appears a blue-ish green colour and is dripping wet, when hit it splashes and ripples as if it were made of water. It has temporary hp equal to half your warlock level plus your charisma modifier and if it ends its turn submerged in water it gains one temporary hp. Its turn is directly after yours, during its turn you control it. You can summon the Specter a number of times per day equal to your charisma modifier (you can have more than one at a time). They all disappear when you take a short rest. 

Drowning aura

At 14th level you can create an area around you that causes peoples bodies to mimic the effects of drowning. It works similar to a voodoo doll except the doll is your patron a few seconds before they died. 2 times per day you can, as an action, activate this aura. When you do, all hostile creatures within a 50 feet of you begin Suffocating (see the rules for Suffocation). This aura lasts a number of rounds equal to your charisma modifier. At level 20 you can do this 3 times a day.