The Leviathan

You have made your pact with one of the most powerful and feared creatures to ever exist in the vast oceans and seas across the world. Its legends are told from the trembling lips of the sailors and sea folk that stumble across watery graveyards of ships and corpses. Some speak of a creature that appears to wreak destruction on those that tread too far into the unknown waters where it makes its lair. Others say that the creature is bound to the will of the sea itself and acts as its protector. Whatever the reasons are behind its actions, those that find themselves connected to the creature become imbued with its raw elemental fury and an appetite for destruction.

Expanded Spell List

The Leviathan 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. 

Leviathan Expanded Spells

Spell Level	Spells
1st	create or destroy water, fog cloud
2nd	misty step, shatter
3rd	tidal wave, wall of water
4th	control water, watery sphere
5th	cone of cold, maelstrom

Bonus Cantrip

At 1st level, you learn the shape water cantrip. This counts as a warlock cantrip for you, but it doesn't count against your number of cantrips known.

Cascading Form

Starting at 1st level, your patron's power begins to take shape in your body, infusing it with the raw energy from the elemental plane of water. You can alter your body to take the appearance and flexibility of flowing water for 10 minutes, though you retain your basic shape, size, and distinguishing features. Your skin and clothing become the color of murky deep water. Anything carried on your person, including armor and weapons, merge into this form and become unusable. While in this form you can breathe both air and water and gain a swim speed equal to your land speed. You can pass through a hostile creature's space regardless of their size, and through a space of no less than 1 inch without squeezing. You are resistant to piercing and slashing damage from non-magical sources and immune to poison damage.

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

Voice on the Waves

Starting at 6th level, your patron blesses you with the languages of the world's oceans and the ancient secrets that lie within them. You can read and speak in the Aquan and Primordial languages, and your speech can be heard underwater in a 30 foot radius around you.

Surging Strike

Starting at 10th level, you can channel the destructive force of your patron into a single attack, dealing devastating damage. You use your action to surge forward like a crashing wave and make a single melee attack against a target. You must be at a minimum range of 10 feet from your target but no further away than your base walking speed, and travel in a straight line. On a successful hit your attack deals 3d10 bludgeoning damage plus an additional 1d10 force damage for every 10 feet of movement spent. The target is knocked back a number of feet equal to half of the movement you spent during the attack. The shockwave from this attack damages all unattended objects in a 30 foot cone beyond the target, dealing twice the damage dealt to them. This attack ignores object damage thresholds and is not deterred by the object's size (such as when attacking a huge or gargantuan object like a castle wall or a ship's hull).

You can't use this ability again until you finish a long rest.

Call of the Deep

Starting at 14th level, you can summon water from the depths of the sea into a creature's body, causing them to begin to drown. You choose one creature you can see within 60 feet of you. The creature must make a Constitution saving throw against your warlock spell save DC. Failure means the target is suffocating and suffers from the stunned condition. The target may repeat the saving throw at the end of their turn. Success stops the creature from suffocating, but they cannot speak for one round as it coughs out the remains of the water. Creatures that do not breathe or that can breathe underwater are not affected by this ability.

You must finish a long rest before you can use this feature again.