The Tarrasque

You have made a pact with a Tarrasque from the material plane, a being whose aims are of pure destruction, even if you strive against such aims. Such a being desires the end of all things, ultimately including you. A Tarrasque slumbers underneath the world in a secret lair. Whether you managed to find its den or came into contact with it by other means it has bound you to its will. How did you form your pact, was it going to eat you, but you escaped? Did you get to its lair on accident or on purpose?

 

Expanded Spell List

The Tarrasque 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.

Tarrasque Expanded Spells

Spell Level	Spells
1st	shield, inflict wounds
2nd	enlarge/reduce, shatter
3rd	haste, call lightning
4th	blight, stoneskin
5th	Wall of Force, hold monster

Tarrasque's Claw

As an action you can make a melee spell attack. On a hit the target suffers 1d8+CHA slashing damage from a spectral claw. This damage increase to 2d8 at sixth level, 3d8 at tenth level, 4d8 at fourteenth level. 

Tarrasque Carapace

As an action you can summon spectral armor stylized like the Tarrasque's scales. This armor lasts for 10 minutes or until you lose concentration (as if you were concentrating on a spell). While the armor is summoned your armor class is set to 15 + your [modifier]Charisma[/modifier]. Also if you are targeted by a Magic Missile, a line spell, or a spell that requires a ranged attack roll the caster must make a saving throw with their spellcasting modifier against your Warlock spell DC. On a fail the spell has no effect. On a fail by 10 or more the effect is reflected back at the caster. At level 10 the spell is reflected if they fail by 5 or more and your armor class is set to 20 your [modifier]Charisma[/modifier]. At level 14 if the caster fails the saving throw the spell is reflected.

Frightening Roar

Starting at 10th level you can, as an action, summon the roar of the Tarrasque. It can be heard from 120 ft away. All creatures within 30 ft must make a wisdom saving throw against your Warlock spell DC or become frightened. 

Swallow

Starting at 14th level, when you hit a creature with an Tarrasque Claw attack, you can use this feature to instantly transport the target into the stomach of your master. The creature disappears into a demiplane in which they take 16d6 acid damage at the beginning of their turn and are restrained. If the target deals damage equal or greater than 60 the target reappears, prone, in their previously occupied space or the nearest their previous space. This lasts for 10 minutes, or until you lose concentration (as if you were concentrating on a spell). Once activated, you can transport more creatures in the demiplane after landing a claw attack on them, but the damage to get out is cumulative. For example is you have two creatures in the demiplane, one does thirty damage the other does forty, they, and any other creature, would break your concentration, freeing them. This feature can be used once per long rest.

 Alternatively a DM could decide that it wouldn't teleport creatures into a demiplane, instead it quite literally teleports them into the stomach of a Tarrasque. This would mean that when spit out, the would be laying prone right in front of an angry Tarrasque they just woke up. 

 

Improved Tarrasque Strike

If you attack with your Tarrasque Claw, as a bonus action you can either do another attack with the Tarrasque Claw, or use the Tarrasque Tail attack. You can do this a number of times equal. to your charisma modifier and regain all uses at the end of a long rest.