Pact of the Deep One

Ancient beings slumber in the seas, waiting in deep abysses since the dawn of time. These beings, called Deep Ones by the few who know of them, have enormous power over the sea and storms. However, the uncountable years of their existence weigh on them like the pressure of the sea above, and the Deep Ones are unable to rise to the surface in order to enact their will. Therefore, they reach out through the waves to the mortals who sail the sea's surface, granting those mortals a fraction of the ancient power available to the Deep Ones. In exchange, these mortals' active minds slowly awaken the Deep Ones' true power. Beings known as Deep Ones include Sekolah, worshiped as a god by the Sahuagin, Olhydra, princess of elemental water, the Hundred-Handed Ones, and the mighty Krakens.

Avatar art by  Marko-Djurdjevic on DeviantArt

Expanded Spell List

The Deep One 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.

Fiend Expanded Spells

Spell Level	Spells
1st	create or destroy water, thunderwave
2nd	gust of wind, shatter
3rd	call lightning, tidal wave
4th	control water, black tentacles
5th	conjure elemental, maelstrom

Deep One's Gift

Starting at 1st level, you can speak, read, and write Aquan. This allows you to communicate with creatures that understand Primordial or any of its dialects. You can also breathe water.

Additionally, you can thunderously rebuke attackers. When a creature within 5 feet of you that you can see hits you with an attack, you can use your reaction to cause the creature to make a Constitution saving throw. The creature takes 2d8 lightning or thunder damage (your choice) on a failed save, or half as much on a successful save.

You can use this feature a number of times equal to your Charisma modifier. You regain all expended uses when you finish a long rest.

Deep Storm

Starting at 6th level, you can call on the deep one's power in battle. When you roll lightning or thunder damage, or bludgeoning damage caused by water, you can reroll a number of the damage dice up to your Charisma modifier (minimum of 1 die). You must use the new results.

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

Channel the Sea

Starting at 10th level, you can draw strength from the sea. While you are in water that's at least waist-deep for you, you can use an action and spend a warlock spell slot to gain 5d6 temporary hit points.

Starting at 14th level, the number of temporary hit points you gain from this feature increases to 7d6.

Thunderous Command

Starting at 14th level, you can channel your patron's power to command all who can hear you. You can use an action to speak in a booming, thunderous voice audible within 300 feet. Any creatures of your choice who can hear you must make a Charisma saving throw against your spell save DC. On a failed save, the target is frightened until the end of its next turn. Also on its next turn, it takes only the actions and bonus actions you tell it to, and it moves only as you command.

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