Yayoi Ulshade is Doctor Ulshade's granddaughter and assistant, aiding him since she was a little girl. When Ulshade gets hospitalized after he returned to Earth, Yayoi takes over her grandfather's task to upgrade Plezuon. She seems to have a crush on Daigo despite her insistence that she is researching his combat abilities. After winning Plezuon over with her Brave, Yayoi takes on the mantle of Kyoryu Violet from her grandfather. Though she initially had trouble transforming due to only wanting please her grandfather at the time, Yayoi is reminded by Daigo's words of why she wanted to be a Kyoryuger and how she managed to manifest her Brave in the first place, allowing her to become a Kyoryuger eventually. Instead of joining the team, she leaves to help her grandfather rebuild his lab while training under the former Kyoryuger.