The Gluttonous One

You have made a pact with an otherworldly entity that have no true shape, only known for its many horrendous forms of countless maws, roves of teeth and an insatiable hunger. The entity known only as The Gluttonous One is a hungering titan whose only wish is to consume everything. It`s grand wish has however, been denied by forgotten forces of old. Still his hunger is so immense and far-reaching that it finds its way into civilizations and worms into humanoids. Others have heard of this entity and sought out it`s gift in exchange of that which The Gluttonous One cannot gain: taste and a filling meal. Through ritualistic consumption of "food", the entity is pleased and grants it`s followers’ powers, however, there is a catch. Disciples of Gluttony goes forever as hungry as their "god" - forever searching for a filling meal that will never come. An endless hunger in exchange for endless power. 
The goals of The Gluttonous One is not adherently evil, but the hunger it feels cannot be fully sated. It`s followers are it`s "maw" in the mortal world and the entity wishes to gobble up everything (and everyone).

The Gluttonous Maw`s Gift of Consumption

Starting at 1st level, The Gluttonous Maw grants you a blessing that is synonymous with itself. Choose one of the following Gifts below. You may gain another Gift at 6th and 10th level. In addition to the gifts, your patron grants you a sizeable maw with the "tools" needed for your gluttonous tasks aswell as a sturdy belly to consume everything. Your teeth become as hard as stone with the appearance of jagged fangs, whose force is enough to crush stone and some metal types. Instead of making an unarmed strike, you can Bite. You are considered proficient with this attack and it deals 1d6 + Strength modifier piercing damage. Your belly and guts become twisted to the point that you are able to consume and process "food" that is not normally counted as food such as: bones, rocks, bark, wood, metal etc. Lastly, due to this change of innards, you become resistant against poison damage and gain advantage on saving throws against being poisoned.

- Gift of Regeneration: You gain regenerative abilities. At the start of your turn, you regain a number of hit points equal to your Constitution modifier (minimum of 1). You do not benefit from this ability if you are on 0 hit points.  

- Gift of The Maw: Your maw is even more akin to your patron. Increase the damage done on your Bite attack from a d6 to a d8. In addition, if you kill a creature with the Bite attack, you gain a number of temp.hit points equal to your warlock level. Lastly, when you use the Bite action, you may attack one additional time as a bonus action.

- Gift of the Bloodgruel: You gain the ability to "consume" spells. Once per short or long rest, you gain the ability to cast the Counterspell spell. It counts as if it was cast as a 3rd level spell. If you successfully counter a spell in this way, you gain temp. hit points equal to twice your Constitution modifier plus casting ability modifier.

- Gift of the Spinemarrow: Sucking out the marrow from a spine grants the warlock and nearby allies better combat proves. As a bonus action, you can consume the marrow from a spine. When you do this, you and all friendly creatures in a 30 feet circular radius centered from you gains +1 to their attack and damage rolls. This effect lasts for 1 minute.

- Gift of Tough Bones and Sinew: Your bones and sinew grow in size and toughness. Your Armor Class equals 13 + Constitution modifier while you do not wear any armor. You may wield a shield and still get this benefit. 

- Gift of The Feast: You gain the ability to summon a feast. As a 1 minute ritual and once per long rest, you are able to set forth a worthy feast for hungering maws. Depending on how many will join the feast, you must spend rations or material worth of ingredients equal to the number of creatures that will join the feast (minimum of 2 and maximum equal to your casting ability modifier plus proficiency bonus). Once the material is gathered and the minute have passed, a grand feast appears within 10 feet of the warlock. Consuming the food grants the consumer 1d12 + the warlock`s casting ability modifier temp. hit points until the next long rest. Consuming the food stops hunger, except for the warlock who will only find a short respite in the feast before the hunger sets in again. At 5th, 11th and 17th level, the temp. hit point dice increases by 1d8.

- Gift of Voracious Maw: The very earth opens up in a gulping maw to consume your enemies! As an action and once per short or long rest, you force the very earth to shape into a snapping maw. Choose a location within 60 feet of you that you can see. All creatures in a 10 feet circular radius must make a Dexterity saving throw, suffering 3d8 piercing damage and have their speed halved until the end of their next turn. Succeeding the saving throw causes only half damage. The warlock regains a number of hit points equal to half the damage done (rounded down). If a creature was killed by the Voracious Maw, the warlock regains hit points equal to half the damage done (rounded up). 
At 5th, 11th and 17th level, the damage dice increases by 1d8.

- Gift of Greater Guts: Your guts swell up and allows you to take more punishment. You immediately gain 10 additional max hit points and you gain +1 additional hit point every time you level up in this class.

Gluttonous Wisdom

At 6th level, you have consumed enough that The Gluttonous One grants you the wisdom of what you have consumed (regardless of what you have eaten). You may choose one 1st, 2nd and 3rd level spell from the Warlock spell list that does not require material worth more than 100gp. Add the chosen spell(s) to your spell list and mark them as "Gut Magic". You may cast one (or more if possible) of the chosen spells as normal with your spell slots, or you may choose to cast it as "Gut Magic". If you choose to cast it as "Gut Magic", it requires no components and does not use a spell slot. You may cast up to two of your spells labled with "Gut Magic" without using spell slots. After a long rest, you may use "Gut Magic" again. 

At 10th level, you may choose one 4th level spell and add it to your "Gut" Magic" list.

Lastly, you gain proficiency in the Constitution saving throw due to your robust guts.

Ravaging Appetite

Starting at 10th level, you can bestow up to your proficiency bonus creatures within 60 feet a portion of your patron`s "appetite". Choose up to two of the gifts from The Gluttonous Maw`s Gift of Consumption that you grant your allies. For the next 24 hours, they are able to use the "gifts" that you granted, in addition to your Bite ability. You, on the other hand, your patron is pleased with your consumption of many delicious treats. The entity sees it fit to further increase your gifts. You gain the upgrades of The Gluttonous Maw`s Gift of Consumption listed below. You still gain the gifts of other gifts you choose in later levels. Your allies do not gain the upgraded benefits.

- Gift of Rapid Regeneration (Gift of Regeneration): Your regenerative abilities are further enchanted. In addition to the regeneration, you can now as an action spend hit dices to instantly heal yourself. Choose the number of hit dices that you wish to use and roll. You regain hit points equal to the number rolled.

- Gift of The Ever-hungering Maw (Gift of The Maw): Your maw grows in size and deadliness. Your Bite damage dice increases from a d8 to a d10. In addition, when you use your Bite action and hit a creature, you can spend a spell slot and roll d8 dices equal to the spell slot used as additional damage. The damage is piercing. 

- Gift of the Bloodgruel Gorger (Gift of the Bloodgruel): Your appetite for spells have grown. You may add Counterspell to your spells known and add it as one of your "Gut Magic" spells. If you had already chosen this spell before, you may choose another spell. The chosen spell still counts as "Gut Magic".

- Gift of the Marrow-render (Gift of the Spinemarrow): The potency of the marrow grows ever bigger. The bonus to attack and damage rolls increases to +2. In addition, all melee and ranged attacks deals additional damage equal to your casting ability modifier (minimum of +1). 

- Gift of Relentless Flesh (Gift of Tough Bones and Sinew): Your flesh and bones are near unbreakable and untearable. As a reaction to you taking damage, you may half the damage done (rounded down). 

- Gift of The Gluttonous Feast (Gift of The Feast): The feast becomes worthy of your patron itself. In addition to the temp. hit points, those that join the feast gains immunity to the frightened effect, removes poisons and, grants the consumer the ability to re-roll one failed attack or saving throw until the next long rest.

- Gift of Ever-feeding Maw (Gift of Voracious Maw): The maw is never sated. You may use this ability twice per short or long rest. In addition, the damage dice changes from a d8 to a d10.

- Gift of The Greatest Gut (Gift of Greater Guts): Your guts are all swollen and near indestructible. You gain resistance against piercing, slashing, and bludgeoning damage from non-magical attacks. In addition, you may add your Constitution modifier times two to your maximum hit points (from when you choose this gift).

Avatar of Gluttony

Starting at 14th level, you are able to become the aspect of gluttony! As an action, you transfrom into a mawed mostrosity and gain the following benefits for 1 minute: 

- You grow one size larger.

- You gain temp. hit points equal to twice your level.

- You score a critical hit with your Bite attack on a natural hit roll of 18 - 20. You may also attack one additional time with your Bite.

- You gain resistance to all damage types, except psychic.

- You are immune to the frightened, poisoned and prone condition.

- Lastly, if you use your Bite action on a Medium or smaller creature (you must be Large or larger for this to take effect), they must make a DC 8 + your Strength modifier + proficiency bonus Strength saving throw or be swallowed whole. Succeeding the saving throw causes the creature to not be swallowed. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside of you, and it takes 8d6 acid damage at the start of each of your turns. You may have two Small or one Medium sized creature swallowed at a time. If you die or are knocked unconscious, a swallowed creature is no longer restrained by you and can escape by using 5 feet of movement, exiting prone. A creature may attempt the same saving throw at the end of it`s turn. If the creature(s) succeed the saving throw, they are thrown up and lands prone within 5 feet of you.

You regain the ability to transform into the avatar after a long rest.