Voidborn

The darkness of the heavens birthed the stars, yet left behind a somber secret. The void, a hungering entity that feeds on the very light that gave life to many worlds. Voidborns are shards of the Void, beings of astral power and knowledge. They appear throughout worlds, sometimes as independant creatures, other times as agents of the void, trying to propagate its will.

Traits

Ability Score Increase. Your Charisma score increases by 2.
Age. Voidborns are birthed sentient and aware, they have no notion of adulthood. Some can live up to 200 years old although plenty of them have never known the release of death.
Size. Voidborns have the same range of height as humans, although they weigh up to 20 times more. Your size is Medium.
Speed. Your base walking speed is 30 feet. 
Superior Darkvision. Your eyes were made to see through the darkness of the void. You can see in dim light within 120 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.
Inconsequential. You are born a mere speck within the endless void of space. You have resistance to necrotic damage.
Vacuous Body. A shard of the void is trapped inside of your body and can act as a pocket dimension. As an action you store or retrieve inanimate objects from inside it. This dimension can hold up to 30 pounds, not exceeding a volume of 1 cubic foot.
Languages. You can speak, read, and write Common and Deep Speech.
Subraces. Voidborns are born with varying powers, separating them in 3 sub-races: Boundless, Sundered and Demise. The DC for abilities given by the subraces is equal to 8 + your proficiency bonus + your Charisma modifier.