Sagara Seiji is a minor character who appears in Happiness Charge Pretty Cure!. Seiji is Megumi's neighbor, and Megumi and Seiji have been friends since kids, and Seiji understands Megumi's weak and good points.
Seiji appears to wear his school's uniform for boys, but on usual day, he wears a red jacket, with dark green pants, and also red sneakers. His hair is similar to Yuko's hair, but more brown. During the summer, he wears a light gray short-sleeved jacket with a red T-shirt underneath with dark blue jeans and red sneakers.
Seiji appears to be calm, and also friendly. Seiji admires the way Megumi helps out people, and how cheerful she is. He has a strong sense of justice and will always lend a helping hand to those in need.
- Seiji is the first male civilian character who knows the Pretty Cure's secrets. He also shares some attributes from Miyuki Chinen of Fresh Pretty Cure!, as both knew the Pretty Cure's secrets in different ways.
- Also like Miyuki, they both have a sibling.
- He is also the second character who join the karate club, after Itsuki Myoudouin of Heartcatch Pretty Cure!.
- He has the first name with Seiji Yotsuba, Alice's father.
- Like Rikka Hishikawa, he often worries about the lead Cure's behavior.
- Seiji becomes a Saiark in Episode 27.
- He was called a knight because he protected Hime just like in Swan Princess.