John Kreese

John Kreese, known as Kreese, is the antagonist of the Karate Kid franchise, and antagonist of the Cobra Kai series.
Kreese is a cruel, ruthless, and unhinged Vietnam War veteran and the sensei of the 1970s/1980s karate dojo Cobra Kai. He instilled a dangerous "no mercy" philosophy in his students and encouraged generations of bullies. Most notably, Kreese taught karate to a teenage Johnny Lawrence and feuded with his karate rival, Mr. Miyagi. After repeated losses at the hands of Daniel LaRusso and Mr. Miyagi, Kreese fled the valley and lost contact with his students.
Over thirty years later, Johnny Lawrence has reopened Cobra Kai, prompting Kreese to make a surprise return to the valley. He eventually acquires the dojo through nefarious means, becoming the Sensei to an entirely new generation of students. With his rivals uniting, Kreese seeks out his old army buddy Terry Silver for help in Cobra Kai, when he spots an attractive girl at Terry Silver's house.