The Deeply Grasped

The notion of a beast so mighty that it can simply drag entire vessels to the briney deep is enough to convince whole crews to stay ashore, so merely mentioning the titan would bring the ire of sailors of all types upon you. That said, there are those who have faced such a beast and lived to tell the tale, if they are to be believed. While most such claims are tall tales, there are those who bargain their souls for their survival in an encounter with a Creature Below. They live, and the leviathan grants them power to exact its will upon the shores.

Expanded Spell List

The Deeply Grasped 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.

Deeply Grasped Expanded Spells

Spell Level	Spells
1st	Create or Destroy Water, Fog Cloud
2nd	Enhance Ability, Enlarge/Reduce
3rd	Water Breathing, Create Food and Water
4th	Watery Sphere, Control Water
5th	Conjure Elemental, Control Winds

Mark of the Deeply Grasped

Starting at 1st level, your Patron bestows upon you the "Mark of the Deeply Grasped" cantrip. This allows you the ability to transform your dominant arm into a tentacle with a five foot reach. The tentacle replaces your entire arm, from your shoulder to the end of your finger. The appearance is similar to your skin-tone. 

Also, you gain the ability to breathe underwater, you have a swim speed equal to your walking speed, and none of your attacks have disadvantage underwater (due to purely the water). 

(Any tentacles you spawn have an AC equal to your Spell Save DC and Health equal to Twice your Warlock Level.)

Spawn of the Depths

Note: This ability only exist if you have chosen the "Pact of the Chain", otherwise this ability will not be available.

If you selected the Pact of the Chain, you have the opinion to have a Giant Octopus as your familiar. The only alternation to it is replacing the"Water Breathing" and "Hold Breath" traits with "Amphibious", and it gains a flying speed equal to its swimming speed and treats the air as if it were underwater for all its traits and features to be used either in the ocean or land. When your octopus uses its ink cloud ability, the ink doesn't obscure your vision. This ink cloud acts like the Darkness spell, if cast out of water. 

Grip of the Master

Starting at 6th level, your Patron bestows on you two ten-foot long tentacles that adorn your shoulders. Simply use your bonus action to summon the tentacles and later banish away. You are considered proficient with unarmed strikes using your tentacles and may attack with them once per turn as either a standard or bonus action for bludgeoning damage equal to 1d4 per tentacle you have + your charisma modifier. Your tentacles have reach over ten feet's long and are able to grapple a enemy if hit, but only either Small or Medium sizes. They deal double damage against objects and structures. You gain a climbing speed equal to your walking speed, provided that you are not wearing medium or heavy armor. You can’t manifest your tentacles while wearing armor unless the armor is made to accommodate them, and clothing not made to accommodate your tentacles might be destroyed when you manifest them. As an action, you can throw a Medium-size or smaller opponent that you grapple with your tentacles. They can throw them a number of feet up to 10 times your charisma modifier, to a minimum of 10 feet. They must make a dexterity check with a DC equal to your spell save DC or take 1d6 bludgeoning damage for every ten feet they were flung and become prone.

At 10th level, you gain three tentacles instead of just two. Then four tentacles at level 14, to which you get advantage on all grapple checks while using your Charisma Modifier instead of the Strength Modifier.

Tentacle Trials

Beginning at 10th level, you gain the ability to call forth tentacles from the depths. The number of tentacles is equal to the number of hostile creatures within 30ft of you, this includes the Spirit from Spirit Grasp. These new tentacles spawn at points of your choosing within 30ft of either you or a hostile creature. 

You gain this ability back at the end of a short rest. 

Call of the Depths

Suddenly the environment floods with water, rushing from cracks in the wall, floor and ceiling. If you're outside, it shoots from a nearby water source. If even that is not a thing, then it bursts from the ground like a geyser. The flood fills a 300ft cube with salt water. From the edge of the cube a Juvenile Kraken spawns and dashes until they reach combat. Once reaching the center of combat, the Juvenile Kraken is free to attack anybody that the Servant of the Deep One (The Warlock) does not perceive to be an ally. If there is no hostile creature to attack, it attacks the player party. 

You can create air bubbles for up to five allies. These bubbles can be moved by the individuals to match their movement speed with a bonus action. 

At the end of combat, you fall unconscious for an hour and can't be woken up except by non-magical means. 
You gain this ability back after an in-game week of rest.