Board Thread:Warhammer 40k General Discussion/@comment-5.65.81.205-20131002091720/@comment-6078851-20131113003347

while it was horus who decided his own fate he had been manipulated, a manipulation that found purchase from horus' disillusionment of emps, a disillusionment that stemmed from empy's secrecy about....well, a lot.

i think it was 100% emps' fault: he personally created the primarchs. granted they grew up in ways beyond his control, ways that allowed some to be corrupted, but without the primarchs, without horus, the heresy would never have happened. if the primarchs had died before being reunited with pops then the astartes would have continued to expand his domain, the heresy wouldn't have brought the imperium to the brink, emps would still be ambulatory, and the galaxy would mostly be controlled by the imperium.

it may be that his greatest mistake was the primarchs themselves. he had already created supersoldiers and it's highly possible he could've created astartes-like warriors without having to go through the primarchs, and avoid the unsightly heresy.