Himiko is a Btooom! player and the female protagonist of the Btooom! manga series. She has a crush on Sakamoto and cooperates with him in the Btooom! game. Her real name is Hemilia.
Himiko always carried a stun gun where ever she goes because she is afraid of being touched by men. Yoshioka-senpai and Mitsuo Akechi have both tried to rape her, eventually resulting in her fear of men, and she said that every man on the island is her enemy. However, she slightly changed her opinion, as she realized that Sakamoto is the only one on the island whom she could trust.
Himiko is a young high school girl. She has bright blue eyes and long, blonde hair, making her look like a foreigner. Her hair is wavy and parted to the right, exposing a part of her forehead. She has small earrings and paints her finger-nails cyan. She has pretty large breasts. Because of her events on the island, she is also covered with small bruises and cuts.
She has only been seen wearing her high school uniform. Her uniform consists of a white buttoned shirt with a small tie around her neck. The tie is dark green and Himiko styled it with an embroided white skull. She also wears a camouflage-colored skirt, that reaches the half of her thighs. She has black, long socks and regular shoes. When her underwear was exposed, it is shown that she wears pink bra panties.
When she and Sakamoto stayed in the deserted building together, she began wearing a white shirt she found in the rations-case. The shirt has a print of a bat on it and reached over her skirt, revealing only a small portion of it.
When Himiko was in high school, she was befriended with Yoshioka and his band, which was well known among the high school girls. One day, she took her friends from school (Miho, Arisa and Yuki) to meet them in their apartment. Himiko had to go to her house in the same building for a moment and left her friends over there. When she came back, she saw the remnants of a party, with traces of alcohol and drugs on the table. When she searched through the apartment, she ended up in the bedroom, where she shockingly saw two members of Yoshioka’s band raping Arisa and Yuki while Yoshioka filmed them. It is implied that the band put roofies in the girls’ drinks. Yoshioka turned to Himiko and tried to drug her too, but Himiko punched him in the face and ran away, only to see Miho pressed against a glass door, also being raped by one of the band’s members. Miho shouted to Himiko to save her, but Himiko was too confused and ran away in despair.
When the incident was exposed and the band was arrested, Himiko’s friends moved away. Himiko saw Miho later on on the street, with Miho telling Himiko that they agreed to put her name up for the Btooom! game.