Assassination Classroom Wiki

Hideki Mizuguchi (水口 秀樹 Mizuguchi Hideki) [1] is the lead delinquent in Nagisa Shiota's Class 3-5 in Paradise High School.


Hideki has a pair of eyes with small pupils and has short black hair with the top part combed backwards.

Like most of his classmates, Hideki sports a black jacket over a patterned shirt along with black pants as part of his school uniform.


Hideki does not like being ordered around by someone he sees as physically weaker than him, but he will yield if he were to be bested as notably shown when he meets his teacher Nagisa Shiota for the first time.


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After letting Nagisa Shiota get mocked by his classmates, Hideki rose from his seat to threaten Nagisa not to order them around, or he would be killed. At that point, his teacher used the Stun Clap on him, maneuvered around Hideki and held him still with his middle finger poking at his neck. Shocked by the sudden turn of events, Hideki is wished good luck by Nagisa before class began.[2]

Some time later outside, Hideki barked at a napping Nagisa to wake up and added that he and class only went outside because Nagisa wanted to study there.[3]


  • The name Hideki means "excellent, outstanding" (秀) (hide) and "tree" (樹) (ki).
  • Hideki's surname Mizuguchi means "water" (水) (mizu) and "mouth, entrance" (口) (kuchi/guchi).


  • It takes two hours for Hideki to style his hair.[1]


  1. 1.0 1.1 Assassination Classroom Official Illustration Fanbook: Graduation Album Time
  2. Assassination Classroom manga; Chapter 180: Killing Time
  3. Assassination Classroom manga; Extra Chapter 4: Time to say Thank you