- Anger is the god of fools.
- — O-Sensei src
There is very little known about his origins, except that he used to work with Barney Ling in the organization G.O.O.D.. He took Ben Turner as a student while living in Japan. They discovered a thief named Richard Dragon trying to steal a statue one night. Dragon attempted to kill O-Sensei, but O-Sensei easily defeated him. Despite this violence, O-Sensei saw goodness in Richard Dragon, and decided to teach him as well. O-Sensei spent six years training Dragon and Turner in combat, history, philosophy, and science. Their training eventually finished, and O-Sensei viewed them as sons, but he was forced to let them go pursue their destiny. His students were recruited by Barney Ling, who used them as agents of G.O.O.D.. They later left Japan to move to America, and O-Sensei said goodbye with tears in his eyes. Dragon and Turner moved to New York City with O-Sensei's goddaughter Carolyn Woosan. It is later revealed that O-Sensei gave Richard two gifts, both items that had been passed down by his old sensei. This included his own uniform, and a powerful emblem called the Dragon's Claw.
- Decelerated Aging: At the time of his death, O-Sensei was more than one-hundred years old. His exact age is unknown, but there are records of his activity as a young man as early as 1895.
- Martial Arts
- Aikido: O-Sensei has mentioned that he is a disciple of Aikido.
- Boxing: O-Sensei has mentioned that he is a disciple of Boxing.
- Jiu-Jitsu: O-Sensei has mentioned that he is a disciple of Jiu-Jitsu.
- Karate: O-Sensei has mentioned that he is a disciple of Karate.
- Savate: O-Sensei has mentioned that he is a disciple of Savate.
- Pedagogy: O-Sensei is an expert at instruction and guidance; restricted towards the teaching of martial arts.
- Philosophy: O-Sensei is an expert in philosophy and zen mastery, in particular in how they relate to Kung Fu.
- Although this character was originally introduced during DC's Earth-One era of publication, their existence following the events of the 1985–86 limited series Crisis on Infinite Earths remains intact. However, some elements of the character's Pre-Crisis history may have been altered or removed for Post-Crisis New Earth continuity, and should be considered apocryphal.
- O-Sensei was created by Dennis O'Neil and Jim Berry as a character in their 1974 novel Dragon's Fists. O'Neil later adapted him as a DC Universe character in 1975 when he was writing the series Richard Dragon, Kung-Fu Fighter.
- 16 Appearances of O-Sensei (New Earth)
- 9 Images featuring O-Sensei (New Earth)
- 2 Quotations by or about O-Sensei (New Earth)
- Character Gallery: O-Sensei (New Earth)