Name: Kaisen
Age: Unknown (though considered a young adult)
Birthday: June 9th (Lockpicking Day)
Height: 183 cm (with shoes) ※ 180 cm without shoes
Weight: 60–61 kg
Dominant hand: Right
First-person pronouns: Boku, Washi / (occasionally) Ore
Occupation: Locksmith
Family: Father, Mother, Older Brother, Younger Brother (Kaisen is the second son)
Speech pattern: A mix of Kansai-style intonation and word choice
Personality: Simple and gentle

His favorite way to spend time is relaxing with you.

A young man quietly running a “locksmith shop” on a dimly lit alleyway. From opening locks to closing them, there’s nothing he can’t handle. Always nonchalant, his true intentions remain hard to fathom.