The Void

Nobody knows what The Void is, or what it wants. But all Void Warlocks work under the guidance of this upper power, and they tend to be very unpredictable. The Void ends up speaking to the Warlock, telling them secrets. (Credit to my friend TheEbonHawke_ on discord)

Dematerialization

Harnessing the power of the void, you can speed up the decomposition time of objects and/or people. At the first level,  Up to your charisma modifier, you can speed up the process of the decomposition on dead or living creatures you touch dealing 1d6 Necrotic damage on a failed Constitution saving throw. If the creature is to succeed on the constitution saving throw, its decomposition stays the same rate it was. 

Extended Spell List

At the first level after taking this subclass, you gain access to the following spells: 

1st: Dissonant Whispers, Fog cloud

2nd: Pass without trace, Immovable object

3rd: Blink, Sending

4th: Edvards Black Tentacles, Morderkainen's Private Sanctum

5th: Farstep, Hallow

Malnourishment

At the 1st level, The Void grants you the ability to go without food or water for months at a time. You have no need to eat, It doesn't fill you, and you can eat a seemingly infinite amount of food. 

Mana Spill

At the 6th level, The Void grants the ability to regain a spell slot from nearby party members. As an action, you can steal 1 spell slot from a party member that happens to have spell slots left, you may need to ask first. You can use this feature Up to your proficiency bonus.

Life Well

The Void takes pity on your mortal body. At the 10th level, You gain access to one of the two styles of the Well of Life. 

Ranged Decompost

When you take this option, you gain the ability to deal more damage with decomposition, and from afar too. you can infuse ammunition with your power granted by The Void. This allows you to speed up decomposition from afar. don't forget, you gain proficiency with Bows and Crossbows, along with gaining the feat: Crossbow expert. 

Tank of the Void

Taking this option, you gain the tough feat along with the addition of your charisma modifier to your armor class. You also gain proficiency with martial weapons. 

Void Null

After The Void sees your true worth with its power, at the 14th level you gain resistance to all damage except psychic when you cast a spell using your spell slots for 1 minute. Also, after casting a spell, no ranged attack can hit you. As long as 1 minute hasn't passed, you nullify any long-range attack that isn't made within the nullification field.