In "Sakamoto Days" Season 1, Episode 5, titled "Source of Strength," Taro Sakamoto faces off against Boiled in a fierce battle to protect his family. Meanwhile, Lu Shaotang fights Obiguro while intoxicated, showcasing her enhanced agility. The episode introduces the Assassin Association's Order and their mission to find the mysterious "X" killer responsible for eliminating numerous assassins. Sakamoto regains his former strength as he confronts his past and prepares for future threats.