An sergeant in the Japanese army who appeared in Shadow Hearts, Kato seems to have been promoted following the death of his superior officer, Yoshiko Kawashima. He seeks to form an alliance that will allow Russia and Japan to become allies and win the war against China. He negotiates with Sapientes Gladio and receives the Emigre Manuscript in exchange for Japan's promise of support. He, with the help of the Japanese government and the Emigre Manuscript, creates three special agents to assist him in his endeavours: the Mutant Apes. After Ouka, one of the Mutant apes, is killed by Nicolai, Kato intends to reverse time to one hundred years ago and create the whole new world, destroying the current one. To do so, he uses the Emigre Manuscript to summon the power of ancient Japanese gods and later turns into Susano-O, the final boss in the game, to battle Yuri. Yuri defeats Kato to stop his apocalyptic plans. In Shadow Hearts he is called Seiji Kato. However, he calls himself Masaru Kato to Kawashima in her death scene.