Masumi Katagihara (樫原 真澄) is the first daughter and second child of Narumi Ioroi and his wife Tamami Ioroi. She married into the Katagihara House, one of the Sanka (which means subordinate for the houses) houses of Ioroi House. Her husband Seishirou is the next head of Katagihara House.
Unlike her most siblings, Masumi resembles her mother. She has curly black bob hair with small tails at two sides.
Masumi is first mentioned by Narumi as "married out", when her siblings and parents are hanging out.
Later she appears in her younger sister Shizuru's flashback, where their father Narumi is severely injured. Masumi and her mother is shown worried and sad.
Masumi and her husband has been seen watching the Hadarae Castle Games alongside her family.