u/Kirbo32

So, I'm coming back to Stellaris after a long time, and thought I'd do another Great Crusade era Imperium run (original, I know). Given I haven't played too much of Biogenesis and 4.0 in general, I'd like to ask, what can a humble servant of the Emperor do to make lore-accurate Astartes? Can be anything, species traits, tradition paths, anything you can think up. Only thing to note here is that this is meant to be a general Imperium run rather than a Chapter, and that the Astartes are not meant to replace the baseline humans, besides that, go wild.