Brennan is a foul-mouthed, lecherous, hypocritical and sometimes violent narcissistic bishop, who frequently abuses his power. He despises Ted, Dougal and Jack mainly because of the problems they have caused, such as Ted stealing charity money and losing it all to gambling, Dougal causing an incident that damaged several nuns and Jack with his obvious alcoholism, violence and horrible attitude, which caused a disastrous wedding. He is greatly feared by Ted, but not so much by dim-witted Dougal while Jack views him with contempt.
He also has a young son with an unnamed young woman but they live in America.
- He has a massive fear of rabbits which stems from him being trapped in a lift with them