John Kreese

Kreese returns in the first-season finale of Cobra Kai and faces his former pupil Johnny Lawrence, who reopened Cobra Kai and went on to win the recent All-Valley Karate Championship.[6][7][8] In Season 2, Kreese ostensibly asks Johnny for forgiveness for attacking him after the 1984 All-Valley Under 18 Karate tournament, in which Johnny placed second. He states that after the original dojo closed down, he re-enlisted in the Army to train Special Forces soldiers and run strikes during the Gulf War and the War in Afghanistan, though he now feels lost as the world has changed around him. Though Johnny rebuffs him for this apology, Kreese maintains that he never tried to kill Johnny and has repaired his second-place trophy to make amends which cools down the animosity between them; Johnny allows Kreese to attend Cobra Kai classes as an observer. Johnny and Kreese encounter Daniel, who realizes that Kreese has faked his death once again.

Later, when the Cobra Kai's students become concerned about Kreese's attitude and his war stories that do not add up, Johnny follows his former sensei to a homeless shelter. Kreese admits that he flunked a psychological test when he attempted to re-enlist in the Army, and that his stories about wars after his Vietnam experience were lies. Feeling bad for Kreese, Johnny decides to put his full trust in Kreese, believing that he wants to change for the better. However, Kreese quickly becomes a negative influence on Johnny's students, seeking out the most resentful and angry students to drive a wedge between the group under the guise of individual tutoring and advanced classes. He later abuses his influence, going so far as to encourage some of them to vandalize the Miyagi-do Dojo. After seeing the tactics used by his students during a training exercise at Coyote Creek, Johnny discovers that Kreese has been teaching the old ways of Cobra Kai behind his back and expels him from the dojo. After Miguel is severely injured in his fight with Robby at school, most of the students lose faith in Johnny and side with Kreese, who reveals to Johnny that he convinced strip-mall landlord Armand Zakarian to take the dojo away from him. Now being its sole sensei, Kreese hopes to return Cobra Kai to the ruthless organization it once was, using the remnants of Johnny's most disaffected students as his core.[9]

Younger John Kreese as portrayed by Barrett Carnahan in Cobra Kai

In season 3, Kreese's backstory is explored. It is revealed that his mother committed suicide and he was an outcast as a teenager, getting called names such as "freak" and "loser". One day in 1965, when Kreese is working at a diner, David, a college football star, his girlfriend Betsy, and another friend of David's show up. After making eye contact with Betsy, Kreese gets chastised by her boyfriend and apologizes. Later, when Kreese is taking out some trash, he witnesses David hitting his girlfriend. Kreese intervenes, causing a brawl to ensue between him, David, and the football player's friend. Kreese ends up winning not only the brawl but also the heart of Betsy.

After arriving in Vietnam in 1968, Kreese and Terry "Twig" Silver get selected by a cruel captain, George Turner, to form a special forces team that conducts direct action missions in North Vietnam. However, during a mission to blow up a North Vietnamese stronghold, things go south when Silver's radio crackles loudly. Kreese has a choice to detonate the explosives and consequently kill Ponytail, another soldier who has volunteered to lay the explosives, and then escape, but the former refuses out of compassion. Consequently, every soldier in Kreese's squad gets captured by North Vietnamese soldiers. Captain Turner rebukes Kreese for hesitating, and continues to chastise him even right after the North Vietnamese captors execute Ponytail. The remaining American soldiers are held captive until 1969, when they are forced to participate in one-on-one death matches on top of a snake pit arena for survival. At one point, Silver is chosen by the Vietnamese to fight Captain Turner. Feeling sorry for Silver, Kreese volunteers himself to fight Turner instead. Before participating in the match, Turner tries to demoralize Kreese and thus score an easy victory by revealing that Betsy died in a car accident not long after he arrived in Vietnam and hid the truth from him to maintain his focus. When the fight begins, the captain, who is well-trained in martial arts, easily knocks Kreese to the floor of the bridge that is suspended over the snake pit. Turner verbally abuses Kreese for his inability to "shed his humanity" and is about to throw him into the pit, but the latter avoids his impending death by stabbing Turner in the leg with a broken piece of bamboo. Kreese punches Turner off the bridge, but the latter manages to hold on. After a U.S. airstrike neutralizes the spectating North Vietnamese soldiers, Turner orders Kreese to lift him up, but Kreese finally learns to follow Turner's advice of "kill or be killed" by kicking him off the bridge. Kreese’s experience with Turner has earned him Silver’s undying loyalty and adopted his Cobra Kai philosophy around Turner’s program.

In the present day, Kreese continues to teach Turner’s No Mercy philosophy. He actively brings Tory back to the dojo by offering free tuition and intimidating her seedy and unscrupulous landlord. His management of Cobra Kai sowed seeds of division within his students’ ranks, which included recruiting Kyler, Robby Keene, and Brucks much to the chagrin of Hawk, and the removal of any student who objected to feeding a hamster to a snake. As a result, Hawk’s loyalty to Cobra Kai is put to question, while Kreese views Tory and Robby as his star pupils. Kreese’s machinations land him squarely in the sights of the LaRusso family and Johnny, leading to a confrontation when Tory leads fellow Cobra Kai students (except Robby) in an all-out brawl against Daniel’s and Johnny’s students at the LaRussos' home.

Blaming Kreese for what happens to his and Daniel's students during the fight at the LaRusso house, especially Miguel, and turning his own son against him, an enraged Johnny viciously beats Kreese and at one point grabs a sai, but is interrupted by when Robby intervenes. Refusing to fight, Johnny accidentally knocks Robby out by pushing him into a locker while evading his attacks. While Johnny is concerned with his son's well-being, Kreese uses it as the opportunity to strangle him. Kreese’s attempted murder is interrupted by Daniel, who has an even match with him. Even with Kreese using glass shards as an improvised weapon, Daniel defeats Kreese using pressure point techniques against him, and barely spares him after being interrupted by his daughter. Kreese agrees to cease hostilities with Daniel and Johnny until the upcoming All-Valley tournament before giving Silver a phone call.