Maiya Hisau

Hisau Maiya is a young woman who acts as Kiritsugu Emiya's assistant during the fourth Holy Grail War. She is cold and professional, which makes it easier for Kiritsugu to act as he needs to.

Little is known about her history, save that Kiritsugu had rescued her from a war-torn land many years ago. When Maiya was a child, she was forced into the army and trained to be a soldier. She later reveals to Irisviel von Einzbern, Kiritsugu's wife, that she had been raped by other soldiers and later lost her child. After rescuing her, Kiritsugu became Maiya's mentor and taught her his way of life.

When Kiritsugu was hired by the Einzberns to obtain the Holy Grail eight years before the Fourth Heaven's Feel, he entrusted Maiya with all his former equipment - in particular, the gun which allows Kiritsugu to employ his Mystic Code.

Role
Maiya reunites with Kiritsugu when he arrives in Japan shortly before the Fourth Heaven's Feel, having prepared all the weaponry he requires for the upcoming Holy Grail War. Armed with a Steyr AUG, she aids Kiritsugu by helping him snipe opposing Masters.

When Kiritsugu attempts to attack Kayneth Archibald El-Melloi at his stronghold, she ends up working with Irisviel to ensure that Kiritsugu's identity remains a secret from Kotomine Kirei. During a subsequent battle to defeat Caster, Maiya captures Sola-Ui Nuada-Re Sophia-Ri and cuts off her arm in order for Kiritsugu to use the woman as a hostage against Lord El-Melloi. After Kiritsugu forces Lord El-Melloi to forfeit in the war, Maiya shoots both El-Melloi and Sola-Ui.

During the last day of the war, Maiya is assigned to protect Irisviel, who is to be the vessel of the Holy Grail. After conversing briefly with Irisviel, they are attacked by Berserker; Maiya is fatally injured attempting to stop the Servant from kidnapping Irisviel and dies shortly after Kiritsugu arrives to try and save them.