Board Thread:Warhammer 40k Novels/@comment-27376167-20151210113237/@comment-24091837-20160416092912

My theory would have that only these lost primarchs wished to actively learn about intelligent Xenos, and maybe even their developmental process from primitive to space flight capable, while their brothers were content to simply destroy them. That may have lead to a major war between the brothers & their legions, especially if the two lost primarchs wholeheartedly turned their back on the Imperial cult, and its notion of a universe populated soley by mankind even though there truly is other intelligent life out there. These primarchs may have felt that mankind could learn from, & perhaps eventually even trade with these intelligent Xenos.