Books like Storm of Iron

I'm a big Graham McNeill fan. His second novel, Storm of Iron is one of his best works, even compared to the later triumphs of his career. This was the novel which introduced Honsou of the IV Legion, one of the most endearing and evil villains to stride the 40k universe. I read Angel Exterminatus - the Horus Heresy prequel, and the sequels in the Ultramarines series before reading this one, so I had a good understanding of what happened. Right and wrong. The advantages of having read Angel Exterminatus make themselves clear early on. Characters like Forrix, Kroeger and Barban Falk (the Warsmith)have changed. Forrix and Kroeger are still recognisable as the men they once were, but Barban Falk has changed enormously. No longer the level-headed voice of reason, he is a almighty warrior on the path to daemonhood. I found many parts involving these warriors of the Heresy quite tragic, such as Forrix's vicious, beleaguered battle with Imperial Fists in the tunnels, where he becomes aware of his own mortality more acutely then ever before, and the (view spoiler)[death of Kroeger, an inglorious and humiliating end to one of the (admittedly insane)greats of the IV Legion, being hacked to death by his personal slave whilst unarmed and unarmoured. He didn't deserve to die like that. Savage madman he may be, but he still possessed a scrap of honour within him. (hide spoiler)]