Edit: I redid some aspects of this painting that were really bothering me. Background is mostly redone, and Sanguinius' face didn't really seem fitting before. Also some general polishing. Thanks to Technorakel for helpful feedback.
Oh hey, I forgot to upload this xD Fun. Anyway, did this after reading one of the recent Horus Heresy novels (Or rather audiobooking it. I has no time for books)
Done in photoshop.