Endorphin (エンドルフィン , Endorufin) is a a fighting skill that Baki Hanma uses.
The skill is a special ability to increase endorphin levels in order to boost ones durability and pain resistance. The user can activate endorphin production within their bodies to inhibit the transmission of pain signals.
Baki Hanma has the ability to release more endorphins in his body by twisting his right ear. For the first time, he felt that experience when he was doing murderous training before fighting Yasha-Zaru the first series. He is the only one character in series that uses the endorphins.