So I've been playing Space Marine this past few days. Great game. Not at all what I was expecting. I would say my top action game of last year. I mean I always aware Gear of War borrowed from it but I didn't know it was to this extent. To be fair I am talking about the overall look not the gameplay.
Anyways, I wanted to get some background info so I looked into various sources (mainly the wiki site) and I find myself attracted by this universe. Now I stopped reading the wiki site because I want to get into this universe so I want to know where do I start? Any particular book series or game series I should look into?
Just a guideline. I already know about the Horus Heresy and the Great Crusade (though not in great detail just the general story of it) and the origin story of some of the Primarchs.