Atsuma is the mother of Takeru Oyama and wife of Takeshi Oyama, as well as a Blood Pointer user. She was the role model for Tesshin Kushiya during his ten years in isolation, and was considered one of the greatest threats to Takeru Yamato upon his revival, despite being a member of Kamigami. She died ten years previous to the start of the main storyline due to some unknown disease, although Tesshin was able to discern that she was already dying during their fight.
Ten years previous to the start of the main storyline, she was challenged by Tesshin on the orders of Ouken Yamato, who considered her to be a threat due to her Blood Pointer ability. She was caring for Inaho at the time, and during the fight shamed Tesshin as a father, asking if his behaviour was that of a parent. During the fight, she must have demonstrated her Blood Pointer ability, as Tesshin was able to imitate her. Soon after, she died due to an unidentified disease.
Blood Pointer - As a member of the Oyama family, Atsuma possessed the Blood Pointer skill, allowing her to drain elements from their environment through her mouth. This ability would increase her strength and healing her if necessary. It weakens the people who she drained the element from.
Expert Martial Arts - Being one of the leaders of the Oyama dojo, Atsuma was very skilled at martial arts. In particular, her greatest strength was claimed to be her right fist, which was considered deadly (Tesshin's attempt to copy her style resulted in a right punch that could blow someone away and cause damage just from the wind pressure).