Arkio's Redemption Equals Death, mixed with a hefty dose of Tearjerker. He knows he's damned forever in the eyes of the Emperor, but doesn't care as long as his brother is willing to forgive him. Rafen gives him this, and he dies happy, and free of the mutations induced by his Chaotic possession.
Red Fury
Knowing that the mutated Space Marines are about to attack Sanguinius's tomb, Dante takes full responsibility for the disaster and tells the assembled Chapter Masters of the Blood Angels' "cousins" (Successor Chapters) that the coming fight is not theirs and they may withdraw from Baal if they wish and leave the Blood Angels to clean up their own mess. Dante is over a thousand years old, one of the oldest and most respected warriors in the Imperium, and all the Chapter Masters tell him where he can stick that idea.
The moment in the fight when Dante saves Seth from falling into the pit, shouting "Brother!" to get his attention — not the "cousin" they had been using — inspiring a (brief!) discussion of whether they should call each other brother, after all the hostilities of the novel. And afterward, when Seth, who had most opposed Dante's request, is the one who declares that they will do it, and declares that these events had been meant to tell that they were not cousins but brothers.
