Quote Originally Posted by Wraith View Post
Of all the World Eaters, Khârn is probably the worst example of a furious, insane psychopath. Sure; prior to and during the Heresy he was every bit as nuts as the rest of his brothers, but after almost dying at the Siege of Terra he came back.... different.
Kharn was in some respects "the voice of reason" for his legion in the period leading up to the Siege of Terra. He was equerry to his primarch, he was the guy who finally broke Angron out of his "kill all own his legionaries" rut that he fell into after the Emperor rescued him from the gladiator planet, and so forth.

In Betrayer there seems to be a strong trend of him being less crazy than the average berserker.