|Birthday Date||August 28th|
|Hair Color||Maroon (Sei)
White with Red streaks (Cure Firedust)
|Eye Color||Orange (Sei)
Red (Cure Firedust)
|Relatives||Unnamed father (Deceased)(Only appears in Seira's flashback)
Himiya Akane(Mother) (Deceased) Himiya Seira (Twin Sister) (Unknown)
|Alter Ego||Cure Firedust|
|Super Form||Freedom Firedust|
Sei has shoulder-length maroon hair tied up in a small ponytail and orange eyes. He is usually seen wearing the girls' school uniform. If not, his winter casual outfit consists of a white shirt, a black hoodie, black pants and red sneakers. His summer casual outfit consists of a white T-shirt, black leggings and black sneakers.
He is a adventurous and brave boy who was not afraid of anything, due to his past which all of his relatives were gone, leaving only Sei and his twin sister, Seira. As Seira formed a band with her friends and went famous, Sei has been always lonely, especially after receiving the news that his only relative went missing on her world tour. Since then, Seira's magical sparrow, Riri kept him company and passed the powers of Cure Firedust to him.
Himiya Akane: She is Sei's mother.
Himiya Seira: She is Sei's twin sister, who is also a drummer in ImagiNATiON, a popular girls' band. She is the previous user of the Firedust Perfume.
"Burning the flame of belief! Cure Firedust!"
Moeru! Shinnen no Honou! Kyua Faiyādasuto!
Cure Firedust (キュアファイアーダスト Kyua Faiādasuto?) is the alter Pretty Cure ego of Sei. He transforms using his Firedust Perfume.
Himiya (緋宮 Himiya?) - "Hi" means "scarlet" and "Miya" means "palace", so "Himiya" can be loosely translated into "scarlet palace".
Sei (征 Sei?) - It means "conqueror".
Cure Firedust (キュアファイアーダスト Kyua Faiādasuto?)- "Firedust" means "the burning dust coming from a burning flame".
- He is the 5th male cure and the 1st crossdressing cure.
- His Firedust Perfume is previously Seira's.
- He resembles Matsuoka Rin from Free!, except he doesn't have shark teeth.