From Monsterforge himself:
The story behind Multiskull is that he's an amalgamation of the spirits of warriors slain in battle... he draws his power from all the dead killed throughout the history of armed combat-- both on Earth and beyond (hence the oddly sized skulls that are present in the figure). He uses the skulls of the dead to constitute a physical form. When a part of his "body" is damaged or destroyed he summons another skull (or skulls) from some forgotten battlefield nearby. He's a darn hard sucker to kill because there's never a shortage of death and destruction in the universe. He's neither good nor bad.... he's just this steaming pile of anger and resentment that has taken a physical form.
Seeing a toy represented in some kind of action scene always made me want that figure that much more. Charles has cemented Multiskull's place in my pocket for the immediate future with this illustration.
Thank you Charles!