Yeah, it's the Lord of Terra and the first Grand Master of the Assassin's :D
He body is based on the Vampire Counts Necromancer with his head taken from the Flagellant kit (the head in the pillory)
The top of his staf is the flame thingy that's on the head of an other flagellant :P
The rest is greenstuff.
The skull in his hand is converted to a servoskull, I only have to ad some wires or something :)
His personal guard is based on the artwork in the Horus Heresy Collected Visions. I first tried to build the Lucifer Black's, but the black didn't work quite well :P