He is the Most Powerful God of the Universe, the god of the soul, the god of aether, the god of the spirit.
He and the other elemental gods, are The Eternials, they created Eternia reality and they are Ancient Gods of Eternia.
All them have equal amounts of power, but Grayskull can control the other souls, so they have a pact with him.

Recipe:
Used MOTU figures - Faker for the body (head, legs and torso), Skeletor for the head.
The accessories are the sword from MOTU figures Skeletor and Webstor armor.
Used TF-BM- Nightscream to get the wings.
Used fabric and FIMO to make the helmet and the skull scepter was made with FIMO.
In the end painted it with Silver paint and draw the details.

Description:
Name: Grayskull

Powers:
Appearance - Changes his appearance from a benevolent god to a skull faced scary god when he uses his full power.

Other powers - has omnipotent aetherial (soul, spirit) powers, he is the Most Powerful God in the Universe, he can control any sentient being, all the souls are on his disposal, the living ones and the dead ones, to use in battle, he can kill reaping the soul from his opponent.

Weapons: Castle Grayskull Key Sword and Grayskull Staff.

Affiliations: The Eternials

To know more about The Eternials, read my blog:

Grayskull Quest
(check my signature in the forums)