Tamashii Yamaguchi (山口 タマシイ), formerly Midori Yamaguchi (山口 ミドリ) is one of the main protagonists of 3*Hearts.
- Gender: Female
- Hair Color: Brown (formerly), Black (currently)
- Eye Color: Green (formerly), Black (currently)
- Age: 14 (Season 1), 15 (Season 2), 16 (Movie)
- Birthday: July 3
- Zodiac Sign: Cancer
Tamashii likes scary stuff, which is why she is a goth. She is also known as Kira Smith in the English dub.
Tamashii used to be named Midori (ミドリ), used to have curly brown pigtails, used to have green eyes, and used to be a girly girl, but it all changed when her family died by a fire, she now has curly black pigtails, and black eyes, as revealed in Dance Party!