Osden was the product of another moderately successful wizard, his father, and his mother. His father, in an effort to overcompensate for his mediocrity with magical ability, had exceptionally high expectations and often demanded abusive levels of conviction of Osden. His mother, a local priestess in the metropolitan center that Osden was born, overcompensated with unconditionally-ego-petting support. The unfortunate consequence of this combinations left Osden to grow into a neurotically arrogant mess. While his alignment is unquestionably good, it is derived from a delusional belief that he is truly and vastly superior to other people and is therefore responsible for making sure they are protected, particularly from their own perceived idiocy.
Another unfortunate side effect culminated in his blatant delusion of superiority. When met with someone who is obviously more powerful than him, particularly with magic-users, he will delude himself in an extremely unhealthy manner to maintain his high level of self-esteem (fragile ego). If presented with a position where he is unable to convince himself of such delusion (which is extraordinarily rare, even when the comparison is plainly obvious to everyone) he will react in a rather unpredictable but aggressively delusional way. He may, if unable to convince himself of his superiority, begin creating delusion about the source of the insecurity. This may include convincing himself that the person is actually an agent of evil and therefore a threat to the poor denizens of the world.
Osden spends his days obsessing over power in an effort to make himself a more effective controller of evil so that he may protect the poor helpless fools from both themselves and this harsh world which is unforgiving against such poor, feeble-minded masses. Osden will always do what he thinks is the right thing, regardless of consequences, because he is obviously the most capable of deciding what that is. As such, he sleeps quite comfortably at night with a clear conscience that all of his actions are 100% justified in the greater good.