opinions? Spoiler: differences between astartes and custodes Cousins. It was true, if one employed a generous licence with the truth. The warriors of the Space Marine Legions were raised through a similar process to the Ten Thousand, albeit in the coldest and crudest imitation. Diocletian had been reshaped at the fundamental level, with perfection threaded through his blood and bred into his bones. In contrast, his lesser cousins among the eighteen Legions were cut open by knives and implanted with false organs, relying on surgical ingenuity and genetic rituals to mimic the end result of better, more painstaking, more complete, work.