Max Ruddiger is a bombmaker who first appeared in “Gina Zanetakos”.
He built the car bomb for Gina Zanetakos. He was traced by the FBI when he called Gina to tell her that he had to change the nuclear material from caesium-137 to cobalt-60. Raymond Reddington offered him a Syrian contract to reveal Gina's plan and call her so that the FBI could arrest her.
Reddington visits Ruddiger at a rehab facility where he is being treated after a car crash. Red wants information about an arms dealer.
He disarms the liquid explosive bomb he built for Bastien Moreau in the UN. He goes through some trouble with it and says he can only do it when he has a drink.
He rigs the explosives to blast through a wall, but gets stalled when he laments he wanted to become a tenor when he was young. (Tulaine was the first lead singer for the band Madness in 1977.)
Liz asks Reddington for Ruddiger's and Tadashi Ito's help to save her and the team. Ruddiger gets together a team of German bank robbers, whom Reddington is excited about because of their notoriety from robbing an unnamed bank. Ruddiger explains he was in rehab with one of the robbers.