Encounter VII: Trump Card Ninja - S1.E8

Sara is kidnapped by the Jyamato. Keiwa, who learned of this incident, rushes to rescue her despite his injuries. He transforms into Tycoon in front of her and fights the Jyamato while trying his best to protect her. At that moment when Sara touches Tycoon's ID Core, she remembers a terrifying moment from the past that he had forgotten. What is the shocking truth behind the past that the Sakurai siblings share?