Durran is very tall at six feet and six inches, broad shouldered and muscled like a maiden's fantasy. he prefers to not go clean shaven.
He's very strong and popular among the men. He earned his crown after leading the Golden Company against a Dothraki Khal at the employ of the King of Saath. After he beat the Khal, the King of Saath refused to pay The Company, believing the walls of Saath would keep him safe. Durrandon led an attack on Saath and sacked the city. As a final act, he took the King's Crown to humble him, saying he didn't deserve it.
Fair, just, calculating. He may be a strong warrior, but he is a savy plotter and understands the political grounds well enough. He had a wife who died of pale mare. He has two kids from that wife, a son of 12 and a daughter of 8. He wields a Maul in combat.
His past is that he's actually an exiled member of the House Wensington who took up the Durrandon sigil. He doesn't hate Targaryens or Baratheons. All he really wants is to go home and raise his kids. He sees the Targaryens as a way to accomplish that goal