- Seemingly unconnected citizens of Tokyo are targeted for bludgeoning by a boy with a golden baseball bat. As detectives try to link the victims, they discover that following the assaults, the victims' lives have improved in some way.
- Tsukiko Sagi (鷺 月子 Sagi Tsukiko?) : One of the central characters of the series, she is a famous, but timid character designer best known for a cartoonish dog named Maromi. She carries a plush toy copy of Maromi everywhere. She is Lil' Slugger's first apparent victim in the series, and the catalyst who jump-starts the plot. Voiced by: Mamiko Noto (Japanese), Michelle Ruff (English)
- Lil' Slugger (少年バット Shōnen Batto?, lit. Young Boy with Bat) : The enigmatic figure the series revolves around. He appears as a grinning, baseball cap-wearing juvenile who travels on golden inline skates and attacks people with a gold-colored metal baseball bat that is curiously bent. Voiced by: Daisuke Sakaguchi (Japanese), Sam Riegel (English)
- Detective Keiichi Ikari (猪狩慶一 Ikari Keiichi?) : One of two police detectives assigned to investigate the attacks by the Lil' Slugger. He is extremely old fashioned and yearns for the simpler, less hurried times; he is often chastised for this by his young and idealistic partner Mitsuhiro Maniwa. Voiced by: Shōzō Iizuka (Japanese), Michael McConnohie (English)
- Detective Mitsuhiro Maniwa (馬庭 光弘 Maniwa Mitsuhiro) : Young, idealistic, and a flexible thinker, Maniwa is the perfect complement as well as foil to the more rustic Keiichi Ikari. He is open-minded and unconventional in his methods. Voiced by: Toshihiko Seki (Japanese), Liam O'Brien (English)
- Maromi (マロミ?) : Maromi is a popular Sanrio-esque mascot created by Tsukiko Sagi. A pink dog with big black eyes and droopy ears, Maromi is a parody of real life イヤシキャラ (iyashi kyara?) (relaxing characters), such as tarepanda and rilakkuma. In Tsukiko's presence (usually when she is alone), Tsukiko's plush Maromi toy walks, rolls its eyes, and talks to Tsukiko. Voiced by: Haruko Momoi (Japanese), Carrie Savage (English)
Inspirations and Derivative work sEdit