Since the incident, Kiritsugu began living with Natalia who trained him to become a mercenary just like her and travel around the world in various conflicts. Due to his unique magic, Natalia creates special anti-magic bullets from Kiritsugu's ribs. During a mission, Natalia and Kiritsugu are assigned to kill a mage who control bees familiars that turn their victims into ghouls. While Natalia boards the plane that he is in from Paris to New York, Kiritsugu heads to New York to kill the mage's associate. Both Natalia and Kiritsugu successfully eliminated their targets. However, the mage have hidden bees in his body which turns the passengers on board into ghouls. Natalia manages to get into a cockpit safely, but with the plane filled with ghouls, she request Kiritsugu to do something for her. As her plane arrives to New York, Natalia and Kiritsugu have a talk reminiscing the time they spent together and the bond they shared. With her plane within his view, Kiritsugu does what Natalia told him to do; destroy the plane to prevent a ghoul infestation with a Stinger but not before he tells her he was glad to have her as his mother. As her plane crashes, Kiritsugu goes into grief of losing another love one.