I've been playing the game for years now and I still have not gotten to beat the challenge, yet I have gotten very close. I would recommend using Wyatt the warrior because of his shield ability wich can help him deflect any attack. Also if you bought the DLC, an old man will be selling perks for all of the characters and Wyatt's perk, also known as steel reflexes. Steel reflexes helps him by getting an armor orb every time he waits for the last moment to defend an attack and blocks it using his shield. Giving him a slight advantage of being able to be attacked once before death. Hopefully I helped by telling my knowledge of the game and that someone may beat the challenge