Hmmm... I think some primarchs would have a much better time than others fighting him, purely because of their fighting styles. I think those that try and tank any of his blows and get nailed by Drach'nyen are gonna have a serious issue. If the anathame and the blade Fulgrim used against Guilliman can be fatal to a primarch, I'm sure that weapon is more than capable of killing one too. Problem is, there aren't really much in the way of feats for post-Heresy Abaddon to give us any real idea of how he compares to a primarch.
Though it should be noted that he was viewed as one of the greatest warriors among the legions during the GC era (that one Dark Angel who's name I forget ranked him along with guys like Sevatar, Kharn, Sigismund etc. if my memory serves me correctly). Not to mention he was the 1st Captain of arguably the most successful legion of the Great Crusade so, despite certain authors depicting him as an Angry Marine in disguise, we can assume that he was more than competent in terms of strategy, intelligence and leadership (though admittedly the last one means little in a one-on-one battle).
Though Abaddon vs the Emperor... yeah, I honestly see Abaddon going the same way as Horus did, because the Emperor would have no reason to hold back at all from the get go. And considering a severely weakened, nearly dead Emperor one-shoted Horus so badly that even his soul was obliterated when the Emperor actually got serious, Abaddon is not winning this one IMO.
The human appendix. Proof of a higher power. A divine kill switch so to speak.
No one really likes a smartass, but people tend to like a dumbass even less.
Last edited by Chompy Bits; 12-26-13 at 04:26 PM.