|This article is about a/an ally in B-Fighter Kabuto.|
Yui Toba (鳥羽 ゆい Toba Yui?) is Kouhei's younger sister and his self-proclaimed manager, covering for him when he leaves school to fight Melzard. She is in love with Kengo. She was frozen by Elebammoth, the first monster sent by the Melzard. She was once put under a spell, when Mother Melzard gave her a pink/white flower armor-themed warrior.