Board Thread:Warhammer 40k General Discussion/@comment-25686730-20141212030710/@comment-24944355-20141212060937

The Thousand Sons is probably the weakest legion I n terms of numbers & most of the numbers they do have are rubric undead, their actual living numbers are probably no more than a few hundred, if that. Despite this they are influential way out of proportion to their numbers due to the fact the few they do have make up most of the top tier sorcerers that chaos has. A single Thousand Son sorcerer has more hitting power than a entire chapters worth of ordinary marines & the most powerful of them, eg Ahriman, would make even Abbadon hesitate before crossing.

As for Magnus he is the most powerful of all the demon primarchs & he unlike the others despises his patron Tzeench & his loyalty to chaos is questionable at best. It's very likely that Magnus is actively conspiring to overthrow Tzeench & replace him as a god of chaos an ambition similer to that of Ahriman the most powerful of chaos sorcerers.