|Kokushikan High School|
|Bats: Right||Throws: Right|
|Age||17 (debut) |
|Date of birth||30 September|
|Place of birth||Tokyo|
|Height||174 cm (5' 8.5")|
|Weight||65 kg (143 lbs)|
|Education||3rd Year High School
Kokushikan Alumni 
|Manga||Act I - Chapter 33|
|Anime||S1 - Episode 12|
|Voice Actor||Takuma Terashima|
Zaizen Naoyuki was a student of Kokushikan High School and pinch hitter of the Kokushikan High School baseball team.
Once a baseball prodigy, he was expected to become the ace and cleanup hitter for Kokushikan. However, he suffered a big knee injury at the beginning of his 2nd year which forced him to sit out the entire season which was supposed to be the one where his talent would truly blossom. At the beginning of his 3rd year his knee has recovered partially, but he cannot play an entire game, so he can only be a pinch hitter.
Zaizen was once a baseball prodigy. He was expected to become a fearsome ace and cleanup hitter for Kokushikan until his knee injury.
This data is based on the official guidebook, it will only be changed if there is an official update!
You are free to write about the characters improvements in the Skills section above!
- Rankings from the guidebook: 
- He ranks second in Contact right behind Kominato Haruichi (thus has a very good ball-meeting ability).
- Favorite Food: Strawberry Daifuku 
- Best Subject: Art 
- He has respect for: Gackt 
- Hobby: Reading manga about Yankees in general