Initially, Brian is a comparatively more grounded and reasonable character, acting as the voice of reason, but a decent friend towards Peter. However, as with many characters, Brian has started to show more of an atrocious side as the series progresses into more of a dark humor series.

He became very egotistical and severely egomaniacal (this may be because of his bad behavior, which he continuously blames on somebody else rather than himself, showing him to be a narcissist), and is show to be 