Bane of Empires
Chaos "gifts" are not just physical mutations that have to be endured by mortal flesh, nor are they only weapons or artefacts. Abaddon bears the Mark of Chaos Ascendant (something Horus never did). As per the post AD-B quoted: He is "surrounded by a coil of ever-replenshing Chaos energy, heralded by choirs of daemons of all powers, suffused with the essence of the four great Chaos Gods. To each worshipper and follower he appears different (much like the Emperor…). He is a schemer, a warrior, a self-centred iconoclast and a survivor."I've always wondered in what sense of the word, the Chaos Gods have given him power. I think its fair that his biggest strength is the influence and sway of chaos forces to his cause. And though he may have some Chaos Gifts, weapons and so forth, I've been always skeptical of how much Chaos power can really be bestowed on him. After all, he is just an Astartes. He is no Primarch who would be able to physically accept more corruption before its body gave out. The Chaos Gods have also been known to be irresponsible with their gifts, and as such, I'm surprised he hasn't turned to a spawn yet.
I think Chaos "gifts" also manifest as favour. We have an example of Abaddon being protected from death by the Chaos Gods (being spirited away before Eldrad could kill him, if that footnote of lore is taken seriously). He bears, perhaps, the most powerful weapon in 40k lore. Daemons fear him. Psykers and sorcerers cannot overcome him. He has the allegiance of the ancient Daemon Primarchs. There are overlaps, I imagine, between what Abaddon has achieved for himself and what the Chaos Gods have gifted him. Was he always destined to be "The Despoiler", the one who ushers in the Apocalypse, or did he, through sheer willpower and determination earn the favour of the gods and that title himself? Did he find and acquire Drach'nyen himself, or did the gods intend for him to wield it? Did he assemble the largest Chaos armies since the Heresy by his own grit and determination or did the gods lend their assistance? Etc. I am more inclined to believe, given the Chaos Gods' general disinterest in mortal affairs, that Abaddon has achieved everything he has (which is much more than Horus, or perhaps any Primarch, ever did) by his own doing. The favour and gifts of the Chaos Gods make him powerful beyond imagining, but he only has gained such favour and gifts because he forced the Chaos Gods to notice him, and fight over him. He has become the king-maker of the Chaos Gods by becoming the greatest Chaos champion ever, and by refusing to ascend to daemonhood.