From eyeballing the three SCs in question, the fact that Abaddon is denied his invulnerable save makes this one a difficult fight for him to win.
He hits first against both, hits on a 3, wounds on a 4, and the C'Tan has a 50% chance to save. The daemonweapon makes it too tricky for me to crunch the numbers in my head, but this means each of Abaddon's attacks has a 16.5% chance to inflict a wound. Of course, C'Tan have 5 wounds, so this would mean that Abaddon would need, on average, to make around 30 attacks.
C'Tan hit on a 4, and wound on a 2 with no save allowed. Each attack has a 41.6% chance to wound Abaddon, so the C'Tan kills him in 10 attacks.
So if Abaddon is spectacularly lucky and rolls a 6 each time for his daemonweapon, only then are the odds (slightly) in his favor because he has higher initiative than both C'Tan.
This analysis is of course incomplete because it doesn't factor in things like the Nightbringer's shooting attack or his ability to make Abaddon run away. But regardless I think the point is clear that Abaddon would need to be very lucky to down a C'Tan single-handedly.
EDIT: Actually, because C'Tan appear to be vulnerable to instant death, I think Typhus would have a far better shot at this than Abaddon. He needs only 8 attacks to kill a C'Tan, but he only has higher initiative than the Nightbringer, so he had better make those hits count because he will not survive the C'Tan's attacks.
You're holding your plasmagun, staring down the barrel, it gets hot. "Phew! good thing I had stuck my gun outside this friggen window to shoot that heretic! Otherwise I might have melted my face off! - OH $%&^! What happened to my hands!?!"
-m3rr3k contemplates whether cover saves apply to "Gets Hot!"
Last edited by Gul Torgo; 05-27-09 at 03:58 AM.