The sea voyager

A warlock subclas dedicated primarily to atmospheric changes for nautical combat and battlefield control.

Mercyful sea

Starting at 1st level, Your patron blesses you with the ability to alleviate the afflicted. you give a sip of sea water to to a living creature that has 0 hit points. The creature becomes stable and then it restors 1d4 hit points, The amount increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4). A creature can be affected once by this effect until it finishes a long rest

If the creature is a humanoid you can double the amount,  the creature must make a wisdom save, on a failed save the creature becomes enthralled and makes a pladge to serve your patron under you (a creature can fail the saving throw voluntarily). On a succes the creature avoids enthrallment, but this enrages your,  patron turning the water into acid causing 1d8 acid damage per dice used in the heal. Any creature that can't be charmed succeeds on this saving throw automatically

The thrall becomes amphibious and gains a swimming speed speed (if it lacked it) equal to their speed in land. They are bound to any ship that you own and can teleport freely from one to another. However they cannot stay in land for more than an hour.

Explorers of the deep

Starting at 6th level, You can cast Water Breathing without spending a spell slot. Once this feature has been used you cannot use it until you finish a long rest

Wind in your sails

Starting at 10th level, your patron magically wards your from and puts you out of harms way. When a creature makes an attack roll against you, you can use your reaction to impose disadvantage on that roll. If the attack misses you, you can inmediatly make a dash action

Once you use this feature, you can't use it again until you finish a short or long rest

Bountiful sea

Starting at 14th level, you can make a sacrifice to gain your patrons favor. the favor depends on the type of sacrifice:

• An item worth 25 gp: you receive an omen about the results of a specific course of action that you plan to take within the next 30 minutes. This results adhere to the ones listed in the augury spell and have the same limitation.
• A pouch with 50 gp: You may contact your patron and ask up to 3 tha can be answered with a yes or no. This results adhere to the rules and restrictions from the commune spell
• A gold or silver necklace (worth at least 100 gp) and a parchment of paper with the name of your destination: Your patron manipulate the currents of the sea and wind to put you on the shortest route to your destination. The destination has to be on the same plane and must be reachable by sea travel
• A small or tiny creature: You regain two spell slot.
• A medium creature: You regain all your spell slots
• A large creature: you gain the benefits of a short rest (once per lon rest)
• A huge creature: once per short rest you may summon a huge or smaller creature with a CR of 10 or lower and native to the underwater for 8 hour. You can use your action to telepathically comand it and you may dismis it without spending an action. If the sacrifice is bigger you may summon a number of creature up to your Warlock level with a total CR of 20 (once per long rest). These feature cannot be used until the summoned creature is gone (dismissed, dead, duration ends)