James Swallow
Deus Encarmine
Blood Angels (series) part 1

On the planet Cybele, the Blood Angels fight a war not only against the forces of Chaos, but against division in their ranks, as one of their own is declared to be the reincarnation of Sanguinius himself.
Warhammer 40k
novel

Also in:
Blood Angels: the Complete Rafen Omnibus