Shutaro Kurusu is a 25-year-old A-class vampire serving in the Imperial Japanese Army's special unit Code Zero. Originally a Nihonbashi wholesaler working alongside his parents, his civilian past distinguished him from fellow soldiers and fostered a gentler mindset. His transformation occurred during military deployment in Siberia when an A-class vampire infected him, leaving a permanent bite mark stigmata on his neck. This event positioned him as a strategic cornerstone in Japan's Kongo Iron Soldier Plan for diplomatic leverage.

As one of Japan's rare A-class vampires, Kurusu joined Code Zero last among its members. His initial combat fragility and moral struggles made his gentle nature a perceived liability, prompting direct training from commanding officer Yoshinobu Maeda. Repeated life-or-death missions compelled him to reconcile pacifism with operational demands, hardening his resolve to employ measured force protecting allies without abandoning core ethics.

Despite his supernatural state, Kurusu clings to profound human ties. His childhood friend Aoi Shirase remains oblivious to his vampirism, yet he safeguards her from afar, upholding a pre-infection letter pledging his survival. This bond anchors his humanity. Physically, he has black hair, vampiric red eyes, and stands 179 cm tall, typically clad in Code Zero’s dark uniform with red accents, occasionally topped by a military hat.

In the mobile game *MARS RED: Edge of the Nightmare*, Kurusu appears as a pacifist supporting character. He guides the newly turned vampire protagonist Yatsufusa within Code Zero’s framework, reinforcing his role as a compassionate figure navigating human-vampire coexistence.