[@Sarpedon] That's a fair enough assessment, but I'd assume his placement as Chief Librarian wouldn't have been possible if he'd been inducted into the Warp Skulls at a later date, such that a Chief Librarian was already in place. This actually ties into something else I'd like to say about the relatively small number of advancement opportunities available to a Space Marine compared to members of a real life army - I couldn't say exactly what ranks there are that a standard Astartes can aspire to off the top of my head, but as far as I'm aware, it's focused enough that even becoming the leader of a squad of ten is rather difficult, and moving up to Company Captain and Chapter Master is obviously nigh-impossible without being absurdly skilful, and perhaps lucky enough to survive beyond your predecessor's death where relevant; this is even more exarcerbated in more restricted aspects of a chapter, namely the Librarians, Chaplains, and Techmarines, the latter in particular having exactly one position to ascend to from the basic rank and file under normal circumstances. I, uh... forget the point I was making with this, but basically, ascension through ranks is difficult for an Astartes, and only somewhat less so when there's a Lieutenant position one may aspire to fill in any given chapter.