Board Thread:Warhammer 40k General Discussion/@comment-6589306-20130228113457/@comment-6078851-20150108143834

about the alliance, i wholeheartedly agree it would almost certainly never happen. it would be hard enough just getting the imperium to ally with every corporeal species, but to then have to ally with chaos too, yeah, not gonna happen. in fact with the exception of the tau i don't see any species that would ally with chaos, even though they have the best, possibly only, chance of defeating tyranids with a chaos alliance.

the hive mind isn't a seperate entity controlling tyranids, but is the amalgamation of every single tyranid psyche in existence - tyranids are the hive mind and the hive mind is every tyranid - and the only way to destroy the hive mind is by destroying the tyranid race. plus, the ultramarines' chief librarian (tigerius?) is the only person to have any firsthand knowledge of the hive mind, and even then it was only the briefest of glances, so to speak, and by and large the existence of the hive mind is largely unknown.

as for the question at hand, it was about tyranids versus xenomorphs, but that ended quite some time ago.