Magnus was always a tragic character for me - Primarch that fired the very opening salvo in Horus Heresy while trying to prevent that very carnage from taking place. Everything that takes place from there on, destruction of Prospero, flight to the Warp to the sorcerers planet and witnessing the new mutations of his Legion, everything seemed to be a punishment for something Magnus did by accident, gigantic tragedy born out of misunderstanding. But in truth all of that was was caused by Magnus' vainglory, his view of himself as the only one with sufficient knowledge to control the Warp and guide the humanity to bright future (this even comes to the surface in his discussion with Ahriman on how he sees post-Heresy events unfolding).

Story confronts Magnus with Malcadore and later with the Emperor. In all these conversations it is visible that Magnus has fallen way lower than he ever thought was the case. When offered only way out and rejoining the Emperor's forces, Magnus refuses it, but while it might seem to be out of love for his sons for me it looks like decision born out of inability to admit that he (Magnus) failed and literally opened the gates of Hell to consume entire universe. And through this refusal he loses the very last traces of humanity and finally fully joins the Horus' team.

Very interesting book, highly recommended to all fans of Horus Heresy and W40K in general. ( )