|First Appearance||SCORPIA uprising chapter 15|
Hiro Masuma was a powerful yakuza thug and member of SCORPIA. He first appears in SCORPIA uprising chapter 15.
He was tasked with setting off an EMP over britain this would wipe out computers especially those with vital information on SCORPIA and Zeljan Kurst. He first sees Alex Rider when he is at his Sushi Restaurant which is a front for his criminal activites. He has his bodyguard Valentine bring Alex to him. He then explains his plans which involve setting off an EMP over britain to do this he would put the EMP bomb on his private jet and it would denonate as soon as the jet goes over britain. Alex and his friend Egar board his plane and defuses the EMP bomb. Zeljan was extremely angry and threatened to kill Hiro if he didn't remedy the situation. To do this Hiro kidnapped Egar and placed her in a room with little oxygen. However Alex breaks her out and goes off for his battle against Hiro. Hiro and Alex do battle aboard his private jet. His bodyguard Valentine Hasashi tries to kill Alex Rider by throwing him out the plane. But Alex manages to hold on for dear life sending Valentine careening to her death. He than proceeds to incapacitate Hiro and shoots the pilot causing the plane to crash killing Hiro although Alex jumped out of the plane and manages to survive due to him parachuting after shooting the pilot.