Max Ruddiger is a bombmaker who first appeared in “Gina Zanetakos”.
Max Ruddiger is an expert German bomb maker and an associate of Raymond Reddington that is always drunk, even while working.
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.
Reddington and Dembe visit Ruddiger for his analysis of a bomb used on a henchman of Red's in Lagos. Ruddiger explains that he works on a new fire accelerant that does not need high temperatures, when they are ambushed by armed henchmen of Neville Townsend. While an injured Ruddiger escorts Reddington into safety, Dembe is caught. After he frees himself from Laken Perillos, Dembe finds out that the van of Townsends men was burned down with Ruddiger's accelerant. Ruddiger is held at gunpoint by Dembe and reveals his forced collaboration with Townsend, having been tortured by Perillos beforehand. Dembe only ties him up after Ruddiger reveals the location of Petrillos warehouse, with Ruddiger stating that Red won't come back.
Rudigger is later brought to Townsend, where he gets heavily beaten in a punching bag as a punishment for Reddington's escape. Townsend afterwards states that Ruddiger's life was only spared because of Elisabeth Keen's pleading and thus welcomes him to his syndicate. Townsend's men then take Ruddiger away.
In a flashback scene, it is revealed that it was Elisabeth's idea to use Ruddiger to get Reddington. After she failed to persuade him to help her, Townsend and his men stormed into the room to restrain Ruddiger. He is then tortured by Perillos. Townsend later uses the bloodstrained punching bag of Ruddiger as a warning for Elizabeth Keen.
“The Russian Knot”
When planing the raid of the museum, Ruddiger demonstrates Elisabeth's team a silent drill machine and gel-based explosives, saying he does not want to fail Neville Townsend again. He then helps Liz in the raid, knocking out Alina Park to save her.