So after a recent thread of mine helped give me a better understanding on the space marines, and to give my guard some speed and beef to them that I feel they've been significantly lacking, I finally got the codex (And some looks at the Angel of Death) and I came up with this combo, which I feel would work quite well! The Space Marines are the main force, thus the Librarian will be the Warlord, which, when surrounded by a ton of fearless conscripts, I don't mind at all! I don't know which Psyker path I'd like them to take yet, but I'm guessing Divination mainly got the great benefits (Twin-linked, rending, 4+
Inv, etc). The Officer of the Fleet is there to hopefully make sure I come on second turn full force, just got to pass that LD7 test for that +1 to reserves!
Space Marines : Iron Hands
Astra Militarum : Allies