Sketchbook 2k15 page 160

The keeper of souls. The souls who cannot decide their fate after death will be conjoined by the keeper of souls. When a soul is conjoined with his their face will appear on the surface of the Keeper of souls. The soul will be purified, or in a another sense, emptied out, thus becoming an object for the keeper of souls collection. 

It is said that the keeper of souls is collecting souls so he could use the souls to build a bridge between the world between the living and the dead. 

The design influence for this character is based on the designs of one of the God Hand's from the manga Berserk. 

The creator of Berserk had his design influences from the movie Hellraiser.