@40kponyguy  
Also, he’s lilac.  
And you do NOT  
I repeat  
NOT  
mess with a god damn man in lilac.  

@40kponyguy  
Yeah. That’s definitely just the artist’s style. Smiling, daemonic, scar covered face with eyes full of ravenous hunger? Yep. That’s Lucius. The whip thing is a minor detail, really. I mean, I don’t imagine he’d have much trouble growing it out of anywhere. ANYWHERE.
 
Yeah, that question’s been in the community for a long time. In all honesty, it likely doesn’t matter. The reincarnation into his murderer’s body is really a gimmick more than anything else. While Slaanesh does enjoy to watch pride turn to anguish before Lucius claims another body, it’s not necessary for Slaanesh to bring him back. The Dark Prince clearly has the power to do it, and this is just the most entertaining way. It’s highly likely that even if Lucius is killed in a way in which the opponent doesn’t take satisfaction, Slaanesh will simply bring him back, regardless. She Who Thirsts wouldn’t just let their fun get cut short because of a self-imposed rule.

@40kponyguy  
The face is covered in scars, much like Luci’s face. Small detail, but it’s there.

@Kharn The Generally Swell Guy  
Thought it would have been, but there’s a couple of things wrong here. Like the face is a mile off, (guessing that’s just down to the artist’s style) and the whip’s growing out of his pauldron. I’m pretty sure Lucius actually carries his whip, but it’s grown in to his forearm.
 
Also, Lucius’ armor is supposed to be covered in screaming faces- all that remains of those great warriors who have actually managed to best him in combat.  
Anyone manages to defeat him, and takes a moment’s satisfaction from that feat, they’ll find themselves slowly turning in to Lucius.  
This raises my question.  
What if Lucius is actually killed by something like a Bloodthirster?  
Or a transcendent C’tan?  
Or an Eldar Avatar?
 
Any of those kills him, he’s gone forever, because daemons do not remain in the mortal realm long enough for him to return using their body, and the other two would most likely regard him with little more than contempt.
 
Tyranids would be another case in point.
 
It wouldn’t be that hard to dispose of this guy using the right forces.

@Kharn The Generally Swell Guy  
Now I see it. Thanks

@40kponyguy  
It’s Lucius the Eternal. The previous two pictures were Kharn and Ahriman, so it only makes sense. Also, the grinning maw and tentacle whip.

@Ashdreg  
Pretty sure that one’s a Slaaneshi Space Marine given the pink coloration and the tentacles….

I’m going to assume this is a chaos space marine