Yumi is a complete opposite of her sister; she has tanned complexion, long blonde hair tied into a ponytail by a clip with yellow flowers and emerald eyes. Matching to that, her nails are also painted in a bright green. She wears the standard female Hyakkaou Private Academy issued uniform, but with the sleeves rolled back.
Yumi is a very cheerful, upbeat and happy individual, which goes in a contrast with her serious sister. She loves Terano unconditionally. She also enjoys staying fit, stating this is her only talent and she doesn't like gambling that much. She often overreacts to situations and doesn't take most things too seriously.
Yumi has a large amount of trust in Terano, claiming to the NPC'S in the Fascination Hall game that if Terano stabs them in the back, they can stab her with a sharp switchblade.
Yumi arrives at the school with the rest of the family planning to take down Kirari Momobami. She herself isn't interested in gambling and is there to take care of her wheelchair bound sister. However, she enjoys the luxurious building and spends most of her time either strolling around or watching Terano Totobami gamble.
During the Greater Good Game, she watches from the sidelines, occasionally laughing from the ensuing chaos. When Miroslava Honebami gives Terano her votes, Yumi awkwardly pats her head. During the later broadcast, she accompanies Terano and is shocked by Sayaka Igarashi's outburst against Yumeko. She is then seen alongside Terano, when she puts her plan with Rei into action and also in the ensuing conversation between Kirari and Terano. When the two later walk down the hallway, they spot the "new" Rei.
When Terano is discussing with the others about their vote buying and the grand tournament, Yumi mentions to Terano, that she sure loves Kirari. Terano sarcastically replies by saying, she loves her so much, she could strangle her. Yumi reacts with an uncomfortable laugh. During the Great Tournament, she strolls down the hall with Miri, who is nervous about Miyo's game against Mary.
- Gambling Girls Again (non-speaking)
- The Girls of the Momobami Clan
- The Girl who Changes (pictured)
- The Treacherous Girl
- The Winning Girl
- The Girl by her Side (non-speaking)
- The Logical Girl (non-speaking)
- The Null Girl (non-speaking)
- Totobami means "class, order, rank" (等) (to) and "bite" (喰) (bami)”.
- The flower hairclip is very similar to the one, Tsuzura has, so they might be the same brand.