If Mike Barnes returns in Cobra Kai season 5, he and Terry Silver will end up just like Johnny and Kreese. Johnny (William Zabka) and Kreese's (Martin Kove) complicated relationship has been a considerable part of both the Karate Kid films and Cobra Kai canon, with their personal journeys as both humans and Senseis at the forefront of Cobra Kai's narrative. The pair went from having a father and son dynamic to being Senseis together before eventually becoming enemies, and if Mike Barnes (Sean Kanan) returns to Cobra Kai, he and Terry Silver (Thomas Ian Griffith) are destined to go down a similar path.
The Karate Kid, Part III's Mike Barnes is one of the last legacy characters from the franchise who is yet to make their Cobra Kai return. Aside from the main characters Daniel (Ralph Macchio) and Johnny having prominent roles in the immensely popular Netflix series, numerous others from the Karate Kid canon have enjoyed poignant returns, including fellow Cobra Kai students Tommy (Robert Scott Garrison), Bobby (Ron Thomas), and Jimmy (Tony O'Dell), as well as Karate Kid II's Chozen (Yuji Okumoto) and Kumiko (Tamlyn Tomita). In this way, as Cobra Kai continues to bring back original actors, Mike Barnes is surely next to return.
Numerous theories have been floated regarding Mike Barnes' potential return to Cobra Kai season 5, and the reasons for him returning vary. Some theories have speculated that Mike could possibly be Miguel's father, while others believe he will be coming back to the Valley to join forces with Terry since Kreese will be in jail. Either way, Mike's return won't be a simple one; and it will likely create issues not just between him and Terry but Daniel and Johnny as well. Although any potential Terry Silver team-up will lead Mike down a treacherous path, if Cobra Kai has hammered home any lesson, it's that people can change, and Mike can too. If Mike has changed for the better like Johnny, he and Terry will eventually end up exactly where Johnny and Kreese's relationship currently lies.
During the Cobra Kai season 4 finale, Mike Barnes’ return is set up as a season 5 villain. After successfully framing Kreese for a crime he did not commit, Terry is now the sole Sensei of Cobra Kai. As police are handcuffing Kreese, Terry states that he won't have trouble keeping the dojo alive because he has some "friends" who can help him out, spawning several theories that one of these friends Terry is talking about is no other than Mike Barnes, a former Cobra Kai student of Terry's. This would make sense given Mike was first introduced in Karate Kid III when Terry hired him from an ad to torment Daniel in exchange for 50% ownership of Silver's Cobra Kai dojos. Terry and Mike's plan failed, as Daniel defeated Mike in The All Valley Karate Tournament, but this doesn't mean that Terry and Mike haven't kept in touch. With both Johnny and Daniel's dojos being disbanded and Kreese being locked up, Terry has an easier chance to completely take over the dojo by calling up Mike unopposed.
Although Johnny has been the main antagonist of the Karate Kid franchise to date, Mike Barnes represents a far more vicious adversary for Daniel and Miyagi-Do despite limited screen time in The Karate Kid, Part III. After all, Mike was selected by Terry personally to torment Daniel when he saw Mike in a magazine, where he was nicknamed "Karate's Bad Boy." Aside from knowing that Barnes is a vicious fighter who doesn't play fair and has won numerous tournaments, not much else is known about his childhood or family - giving Cobra Kai season 5 free reign regarding which direction to take Barnes' character.
Cobra Kai is a comedy, but at the end of the day, Cobra Kai is also a show about generational trauma that breaks down the walls of its antagonists. This is seen in many instances, particularly with Johnny, Kreese, and Tori (Peyton List). The series points to the fact that while all people are flawed in one way or another, even the worse people can change for the better. In this way, Netflix's Cobra Kai also has significant themes of growth and shedding toxic influences, which is exemplified best by, who has had the most intense character arc in Cobra Kai. Although he began the series as the main antagonist who wanted to start a dojo to seek revenge on Daniel, he has grown into a completely different person who wants to be a Sensei for the well-being of his students.
Many years have passed since Karate Kid III, and change comes with time. At first, Johnny was brainwashed by Kreese's toxic lessons of Striking First in early Cobra Kai seasons, but he has since been paving his own way via Eagle Fang Dojo and positively influencing his students. If Mike teams up with Terry, this gives Cobra Kai a perfect opportunity to not only give audiences context on Mike's background and family but can also serve as a starting point for his eventual and inevitable growth.
In this way, Cobra Kai's main themes ensured that when Johnny eventually learns of Kreese's true intentions, he turns on him, and Mike will likely turn on Terry in the same way. When Johnny first teams up with Kreese in Cobra Kai season 2, Johnny thinks Kreese has changed and become a better person, just as he has. It is later rammed home by Cobra Kai's narrative that Johnny was obviously wrong, with Kreese's Cobra Kai mentality remaining unchanged as he viciously pits students against each other for his own benefit.
Over thirty years have passed since the release of Karate Kid III, and Mike was just a teenager during this time. He was also essentially bribed by Terry, as he was just an impressionable kid. Just as Johnny has grown into a better and happier man, Mike can too. Although he may begin in Cobra Kai season 5 as an antagonist alongside Terry, Mike Barnes will eventually see through Terry Silver's thin facade as well.