Board Thread:Warhammer 40k General Discussion/@comment-64.121.236.162-20140910042956/@comment-8881468-20140910095232

ultramar is 500 worlds

and guilliman is the administrator of all primarchs, he is the one with the biggest recruiting base and the most effectiver governor, that simply gets the numbers up. .. simple enough

this has nothing to do with other legions going into the ultramarines (sidenote, their gene-seed would be different from guilliman's and everybody would know of the different marines among the ultras) (chaos marines even have that with honsu, the imperial fist among the iron warriors)

also the back crusades were never really disastrous, most of them, at least the ones led by abbaddon achieved victores and objectives.

if we go through the other legions,  they do not have as high numbers or a recruiting base in the first place and as all chaos legions need loyal gene-seed to swell in size, the ones with most action also  have the possibility to take the most gene-seed   maybe the black legion even takes in  traitors from newer chapters and whatnot.

the thousand sons are mostly rubric marines

the empi children simply too self centered to work as a unit

all khornate berserkers pledge fealty to angron