Maria Oosawa is a central character in the series and the closest friend of the protagonist, Canaan. She is a 21-year-old Japanese woman with long blonde hair and golden-brown eyes, and is frequently seen with a warm, smiling expression. Two years before the main events, she was kidnapped by terrorists during the Shibuya incident and infected with the deadly Ua virus, but she survived thanks to an experimental anti-virus developed by her father. Prior to that incident, while traveling in the Middle East, she was saved from hoodlums by Canaan, which sparked a deep friendship between them.

Maria’s lifelong dream is to become a photographer, and she works as a journalist, partnering with the seasoned reporter Minoru Minorikawa. Their assignment in Shanghai to cover an international anti-terrorism summit leads her to reunite with Canaan. Maria greatly admires Canaan and wishes to shine as brightly as she does; this admiration fuels her determination in her own career and her desire to stay close to Canaan despite the dangers surrounding her friend.

In terms of personality, Maria is curious, determined, and possesses a strong sense of justice. She is compassionate and empathetic, often placing herself in harm’s way to uncover the truth and protect others. Although she lacks combat training, she proves resourceful and courageous, frequently assisting Canaan by using her journalistic skills to gather information and expose a conspiracy involving a lethal virus. Her kindness and warmth help balance Canaan’s more stoic and violent nature, and the two develop a bond of mutual trust and protection.

Maria’s role in the story is that of an ally and emotional anchor. She is not a fighter but a civilian caught up in a larger conflict, yet she refuses to retreat from danger. Through her investigations, she contributes to unraveling the plot, and her presence gives Canaan a reason to fight beyond revenge. Over the course of the series, Maria grows from a reporter simply chasing a story into someone who actively risks herself for the sake of her friends and the greater good. After the events in China, she returns to Japan and opens a photo gallery, creating a portrait series titled Canaan that reflects on her experiences and the friendship she shares.

Maria Oosawa does not possess any supernatural or exceptional physical abilities; her strengths lie in her observational skills, persistence, and the emotional resilience that allows her to stand alongside a mercenary in a world of violence and intrigue.