Fate/Zero

After leaving the island, Kiritsugu began living with Natalia, who trained him to become a mercenary like her and traveled around the world on various missions for several years. Due to his unique magic, Natalia removed several of Kiritsugu's ribs and uses them to create sixty-six magic bullets that have a devastating effect against magi. Later on, Natalia and Kiritsugu were assigned to kill Odd Vorzak, a Dead Apostle mage who controls bee familiars that turn their victims into Ghouls. While Natalia boarded the plane that Vorzak is taking from Paris, Kiritsugu headed to the destination of New York to kill the mage's associate there. Both Natalia and Kiritsugu successfully eliminated their targets. However, Vorzak was concealing bees in his body, which turn all the passengers and flight crew into Ghouls, forcing Natalia to secure herself in the cockpit and await for Kiritsugu to carry out his plan. As her plane drew closer to New York, Natalia and Kiritsugu talked via radio, reminiscing about the time they spent together and the bond they shared. When her plane was in view, Kiritsugu used a Stinger to blow up the plane in order to prevent a citywide infestation. Before he pulled the trigger, he told her he was glad to have her as his mother. Kiritsugu then collapsed in grief over losing another loved one.