- "You're the one that got me into karate, remember? I mean, I was perfectly happy playing Dungeon Lord after school, but you put me in a situation where I had to join a dojo. And you know what? It was the best thing that ever happened to me."
- ―Demetri to Eli[src]
Demetri Alexopoulos is a main character in the Netflix series Cobra Kai. He is portrayed by Gianni Decenzo.
After being the victim of bullying for years, Demetri joined Cobra Kai Dojo alongside his friend Eli, though Demetri left after disagreeing with the dojo's ethics. He later joined Miyagi-Do Karate in the hopes of learning self-defense. He often serves as the moral compass of the group, believing that violence should be a last resort.
Demetri was born likely at some point in 2002. He was best friends with Eli Moskowitz, whom he knows since kindergarten, and they were both stereotypical unpopular nerds. The pair even donned themselves as "binary brothers" and excelled in academia together, winning a coding competition at a computer camp. Their nature as outcasts didn't bother them until high school, when the bullying that they had endured worsened.
Demetri is friends with Eli. He soon meets and becomes friends with Miguel as well, despite warning Miguel about his lowly social status. He is regularly bullied by Kyler, but doesn't feel like there is anything he can do about it. After Miguel beats up Kyler and his group, Demetri decides to join the Cobra Kai Dojo but soon quits after he is embarrassed by the sensei Johnny Lawrence. Miguel tries to convince Demetri to rejoin Cobra Kai but won't listen and tells him that he doesn't need to learn Karate because he has Miguel when he points to Kyler who walks in different direction when he saw Miguel. In the episode "Different but Same", he is shown to have a crush on Yasmine. After Miguel wins the All Valley Karate Tournament, he tells Miguel he might possibly join Cobra Kai again.
Demetri celebrates Cobra Kai's victory in the All Valley tournament with Miguel, Aisha, Hawk and other the Cobra Kai members. He soon decides to join again. When he goes back to the dojo to enroll he sees Johnny's sensei,John Kreese, though he does not know who he is. He is happy to see him instead of Johnny as his last encounter with him ended badly. He first tells Kreese his conditions and expectations, but after looking at his tattoos he tells him how anatomically incorrect they are and even touches them. However, an annoyed and angry Kreese hits him. Demetri complains to Hawk about what Kreese did, but Hawk shows no sympathy for him and tells him to man up.
Having had enough with the bullying, Demetri joins Miyagi-Do Karate and writes a negative Yelp review of Cobra Kai, which angers Hawk. However, Demetri initially struggles and does not look interested. When its sensei, Daniel LaRusso asks him why he is here, he talks about how he has been bullied, and now he lost his best friend because of Cobra Kai, and now wants to prove he can fight back. Daniel tries to give him encouragement, but Demetri is not confident.
While Demetri, along with Miyagi-Do students Robby and Samantha LaRusso (Daniel's daughter) are eating in the mall, he goes to the comic book store. While there, Hawk and a few other Cobra Kai members surround him and force him to take down his Yelp review of Cobra Kai, but when Demetri refuses, Hawk attacks him. Demetri runs away, but is soon cornered by them. However, Robby and Sam defend him and beat up the Cobra Kais.
When Chris, one of the Cobra Kai's who bullied him in the mall, join Miyagi-Do along with four other former Cobra Kais (Nathaniel, Frank, Abe and Lil Red); Demetri, Robby and Sam are unhappy, but Daniel lets them join. After Demetri gets into an argument with Chris, Daniel decides to tell them the time he joined Cobra Kai in order to show how everyone Cobra Kai can corrupt people, and people can change. Demetri then starts to get along with Chris.
Over time, Demetri is able to apply his intelligence to his training, which boosts confidence. During a party at Moon's house, Demetri attempts to bond with Hawk again by talking to him about "Doctor Who"; his attempt seems to work as Hawk is interested. However, after he suggests to Hawk to have inner peace, Hawk dumps beer on his head. Fed up with his treatment, Demetri gets back at him by taking a mic and announcing to everyone all the embarrassing stories about Hawk. An angry Hawk tries to attack him, but Robby and Chris stop him, and the cops arrive. Hawk threatens Demetri that he will beat him up at school.
When a school brawl between Cobra Kai and Miyagi-Do occurs the next day at school, Demetri gets Mr. Palmer and asks him to stop the fight, but he refuses after watching Cobra Kai student Doug Rickenberger taking down a teacher (which even Hawk is shocked by). When Hawk spots Demetri, Demetri runs away and Hawk chases him. Demetri tries to hide in the computer lab, but Hawk finds him. Demetri runs away again. However, Hawk eventually catches him and starts attacking him. After being hit twice, Demetri uses Miyagi-Do Karate to block and counter all of Hawk's attacks before kicking Hawk into a trophy case. Demetri then sarcastically apologizes to Hawk and calls him by his real name.
Demetri is still at odds with Hawk. However he is becoming friendly with Yasmine, due to her lack of popularity. In the cafeteria he shows off his dinosaur valley project/diorama, which impresses Moon and to an extent Yasmine. Hawk then destroys his project, upsetting Demetri, who mocks his sleep enuresis. Later that day (most likely), he gets revenge on Hawk in a soccer game by calling him a loser that lost the 'hottest' girl (Moon) in the school, and then pushing and leg sweeping him. However, he is then headbutted by Hawk. Unfortunately for Demetri, Sam and two other students, they get detention, but skip it and do karate training which Sam runs while Daniel is at Okinawa, while Hawk and his friends are off the hook.
One day, when Hawk, Mitch, Mikey, and Doug are causing trouble at the arcade where Chris works, Demetri, Sam, Stiven and an unnamed Miyagi-Do student arrive to help Chris stop the Cobra Kais. Then, a fight emerges between both dojos. While Chris is beaten to the ground by Mitch and Doug, and Samantha freezes and suffers a panic attack over her past fight with Tory in the West Valley High karate war, Demetri kicks Mikey to the ground, before facing Hawk, who easily pins him to the ground and grabs his arm. The other Cobra Kai's encourage Hawk to break his arm, including Tory, while Demetri pleads with him not to and tries to get Hawk to remember their old friendship. After momentarily hesitating, Hawk breaks and dislocates Demetri's arm after being peer pressured by Tory and the other Cobra Kais, causing Demetri to scream in pain, but Hawk shows some discomfort as Demetri screams in pain, showing remorse for taking this out of hand with his former best friend.
Demetri shows up to school with a cast, and tells Miguel what Hawk did. However, he is bullied by Kyler, who draws a penis on his cast and shows it to everyone, causing them to laugh with the exception of the other Miyagi-Do students, and smacks his head. However, Kyler's bullying earns Demetri the sympathy of Yasmine, who knows how it feels to be a laughingstock since the wedgie incident, as she was mocked on the first day back by Nate and Chris. Yasmine then signs and counter-graffitis his arm cast and covers Kyler's vandalism, making him happy. One day Demetri and Yasmine are caught kissing by Miguel and Sam. Yasmine walks away embarrassed, while Demetri tells Miguel and Sam he is in love, and reveals that he and Yasmine are dating.
On one night, when Demetri (who is no longer wearing the cast) and other Miyagi students are at Sam's house, Miguel and his fellow Eagle Fang Karate students show up via Sam's invitation, where Sam tells everyone that they should all work together. However, the group sans Sam and Miguel don't agree with this. When Mitch and Bert attempt to leave, Demetri convinces them to stay by making a speech about they need to work together and stand up to Cobra Kai. Then, several Cobra Kai's show up and attack them. Demetri is able to hit and fend off a few Cobra Kai's, but is soon cornered and and attacked by Doug and another Cobra Kai, with the former grabbing his arm (same arm that was broken by Hawk). Doug encourages Hawk to attack him.
- "Tory: You better watch your back.
Demetri: He won't have to. He's got friends watching it for him."
- ―Demetri defending Hawk[src]
However, realizing that what Kreese is doing is wrong and that Johnny was correct about making Hawk who he was, as well as that Kreese doesn't care about him and Miguel telling him about how he's gotten in his head, he saves Demetri by knocking down the two Cobra Kai's. Demetri is reluctant to trust him but Hawk then apologizes to Demetri for everything, resulting in their friendship being rekindled, and the two work together to defeat several of Hawk's now former classmates. Then, Demetri, Hawk and Miguel run to the Miyagi Training Building in the back of the house after defeating the Cobra's, where Sam has just disarmed Tory. Hawk tells Tory that the fight is over. Tory stops and threatens Sam that their rivalry will never end and tells Hawk to watch his back, to which Demetri says Sam and Hawk have friends watching out for them.
The following morning at Miyagi-Do, Demetri and Hawk high five and hug, same with Chris and Mitch, and Bert and Nathaniel, who all become friends again and unite in one dojo being run by both Daniel and Johnny.
Demetri and the rest of Miyagi-Do are training with Eagle Fang for the upcoming tournament. He and Sam are circling each other much to Johnny's confusion. He tells him that they need to be provoked in order to go on offense. Johnny then throws a bottle in order to get mad. While Hawk is having a water break, he notices a painting in Miyagi-Do and Demetri explains it's a sparring deck in Okinawa. After Hawk is scolded by Nathaniel and Chris, he looks at Demetri but leaves. Demetri, Sam, Hawk and the others then build an Okinawan sparring deck, helping the dojos work together.
During training, Johnny brings them to a rooftop and has them jump from one roof to another. Knowing how dangerous it is, Miyagi-Do refuses. However, after Daniel texts Sam, she then jumps to the next roof, impressing her and the others.
In another training session, Miyagi-Do is doing combos with Johnny but when he gets distracted watching Miguel train with Daniel, Demetri accidentally kicks him. In retaliation, he ties up Demetri and his classmates use him as a punching bag. He is then hanging out with Miyagi-Do and Eagle Fang at a drive-in where they end up in a confrontation with Cobra Kai. He, Miguel, Hawk and Sam leave after drenching the Cobra Kai's with sprinklers.
Demetri is also in attendance watching the rematch between Johnny and Daniel. When Hawk arrives, he sees his mohawk nearly removed. After realizing the merge didn't work, Eagle Fang leaves.
He visits Hawk to explain about the updates of the All-Valley tournament and shows nervousness about fighting former Miyagi-Do student Robby Keene. Hawk then reveals he cut out the remains of his mohawk, reverting back to Eli and tells him that his time as Hawk made him ruthless to Miguel, Moon and even Demetri. However, Demetri tells him he already forgave him but Eli tells him he quit karate. He then tells Eli that he was the one that got him into karate, which has helped him gain confidence, strength and also win Yasmine. Demetri shows his excitement for the tournament but he tells Eli it won't be as exciting if he doesn't participate. Left with no choice, Demetri then shows Eli their old binary brother video and tells him that regardless of his name, they will still be binary brothers, while also telling him that his mohawk never defined who he was. Inspired, Eli then returns to karate and joins Miyagi-Do. During a tournament simulation, Miyagi-Do is cheering for Demetri when he is sparring with Daniel but ends up getting hit. The rest of Miyagi-Do are happy when Eli joins the dojo.
Due to the updates of the All-Valley Tournament, Demetri needs to participate in the weapons display section of the skills competition, so he's given a pair of sai and starts to train under the tutelage of Sam.
Demetri and Eli are at the prom where Eli tells him that going to prom without a date is embarrassing. Yasmine reunites with Demetri and he dances with her and Moon.
On the day of the All-Valley, Demetri shows off his weapons skills in the skills competition. Before Eli's match against Miguel, he tells Eli is that it's not helpful how no one has beaten Miguel. He advances to the semifinals where he faces his former classmate Robby Keene. In the first two rounds, Robby easily scored two points. After this, the ref gives both fighters a timeout to go talk to their sensei's. After being advised by Daniel to go back to his fundamentals, Demetri fights better and takes Robby down in the third round, but Robby recovers and defeats Demetri. He watches the sudden death match where he's holding Eli's gi and then celebrates with Miyagi-Do after Eli wins the boys division.
- "Oh, I say a lot of things. Which tends to be a polarizing attribute of mine."
- ―Demetri to Eli Moskowitz[src]
Demetri is a sarcastic and awkward person with low self-esteem. He considers himself a jaded realist who is painfully aware of his social status and physical demeanor. He hates confrontation, fights, and finds arguing to be a waste of time. He doesn't tolerate insults or overtly masculine environments. He has low-self esteem and doesn't see himself as more than what he appears - social pariah and nerd. He has a sharp wit, keen sense of sarcasm, and provides intellectual commentary.
He quickly tires of the bullying he receives from Hawk, his former best friend, and joins Miyagi-Do to learn self-defense. It helps him grow as both a fighter and as a young adult, with his confidence and self-esteem growing. When he is humiliated by Hawk at Moon's party, Demetri takes a stand by telling humiliating stories about Hawk as a child. He exposes their secrets and shared memories, knowing the truth of Hawk's formerly "nerd" days would embarrass Hawk far more than any physical fight. Demetri also refuses to call Eli "Hawk", instead, always using his real name to remind the teen where he came from.
Demetri's most admirable trait is his capability for forgiveness and ability to let go of grudges. Despite the horrendous actions that Eli inflicted onto Demetri, the latter accepted Eli back as his friend with open arms. He was there to support Eli, help him assimilate back into Eagle Fang and later Miyagi-Do, as well as, helping Miguel do the same thing after his Cobra Kai stint earlier in the year. Demetri is also a kind and generous boyfriend, loyal to those he cares for, and fiercely protective of his friends.
Demetri is not a natural-born fighter. He is never seen fighting until he joins Miyagi-Do, and even there he struggles with technique. However, he does benefit from his sharp intellect, instantly deducing that Daniel's painting and sanding chores are muscle memory exercises. Daniel eventually makes use of Demetri's intelligence, presenting a blocking drill as a puzzle to be solved. This helps Demetri become a fairly solid defender, making him the opposite of the aggressive Hawk. During his fight with Hawk, he successfully uses the Miyagi-Do technique to counter all of his former friend's strikes, finally defeating him by kicking him into a trophy case. Demetri's lack of strength is compensated by his speed; he is a very fast runner. Demetri is able to consistently outrun people, including five physically fit Cobra Kai students.
Demetri's skills continue to improve, as during the LaRusso house fight, he holds his own while also defending the smaller Bert and Nate at the same time, swings Bert around for higher kicks, and manages to take down several Cobra Kai after teaming up with a redeemed Hawk. Despite the merging of Miyagi-Do and Eagle Fang Karate, Demetri doesn't really take anything from this brief alliance as he primarily uses his Miyagi-Do style. After the two dojos split due to disagreements between their senseis, Demetri is seen as one of the best shots at defeating Robby Keene at the boys division of the All Valley Tournament, showing that he is one of the best male fighters at Miyagi-Do until Eli joins. During their training for the new skills competitions of the tournament, Demetri becomes adept with the Kamas for the weapons display category. He successfully displays his skills with the kamas during the skills competition of the All Valley Tournament. During the individual fights at the All Valley Tournament, Demetri manages to make it to the semifinals and fights former classmate Robby. While he throws some solid kicks, blocks some of his attacks and even maneuvers Robby's body down, though he is still unable to land any hits on him, and is ultimately defeated due to the latter's superior strength, skills and experience.
- "You're my binary brother, whether you're a number one or zero."
- ―Demetri to Eli[src]
Demetri is Hawk's brother figure. They were best friends for many years due to their similar interests and shared popularity status. They become friends with Miguel and join Cobra Kai together, though Demetri quits after being embarrassed by Johnny. When Demetri quits, he begins to vocalize his disapproval for some of Hawk's new behaviors. At the All Valley tournament, Demetri is seen cheering on his best friend, but also sees firsthand how far his friend is willing to go to win. Their friendship becomes strained when John Kreese begins teaching Hawk, and the mentality of the dojo shifts to be more merciless and cruel. Hawk begins to insult his friend and verbally abuse him, seeing Demetri as the culmination of everything he's being trained to hate - a weaker nerd.
Demetri joins Miyagi-Do and their friendship officially ends. Demetri writes a bad review about Cobra Kai and refuses to take it down. As a result, Hawk attacks him in the mall along with some of his Cobra Kai friends. Demetri's attempts to repair their friendship are fruitless, with the pair ultimately fighting during the school brawl. Things worsen, with each taking cheap shots at one another in the name of revenge. During an arcade fight, Hawk places Demetri's arm in a lock and is pressured by his dojo friends to break it. Demetri begs him not too, though Hawk does it anyway. He shows some remorse as Demetri lay writhing in pain. This is a turning point, with Hawk beginning to question the teachings of his new sensei, regret for Demetri being in a cast now evident. During the LaRusso house fight, Hawk is presented with a parallel moment - two Cobra Kai's have Demetri in an arm lock. They offer a free shot to Hawk, who shocks everyone by saving Demetri. Though reluctant, Hawk apologizes to him for the past and offers to help Demetri win the fight. Afterward, Tory threatens that Hawk should watch his back. Demetri stands up to the girl as Hawk has friends watching his back for him.
Demetri helped Eli earn the trust of the two dojos again by looking over the design he created for an Okinawan sparring deck. When Eli's confidence is depleted and his ego shaken following the loss of his mohawk at the hands of Cobra Kai, Demetri is there to not only comfort Hawk, but help him regain some of his confidence by saying that said mohawk didn't define who he was, and assures Hawk that they are still "binary brothers" and always will be regardless of whether he calls himself "Hawk", "Eli", or something else entirely; whether he's a zero or a one, they're binary brothers. Hawk takes this to heart and joins Miyagi-Do as a result. During the All Valley Tournament, they both cheered for each other and Eli tried to help Demetri in his fight against Robby with a Star Wars reference. All this shows that after their reconciliation, their friendship and brotherly bond is stronger than ever.
Miguel is one of Demetri's best friends. After meeting in the cafeteria in season 1 of Cobra Kai, Demetri and Eli quickly befriend him. Miguel is something of an outcast, which helps him bond with Demetri. Halfway into the season Demetri attempts to join Cobra Kai after witnessing Miguel beat Kyler and his gang, but ends up quitting after being humiliated and physically hurt by Johnny Lawrence. Despite quitting he remains close with Miguel, and even tells Miguel that he doesn't need Cobra Kai because he has him.
After the school brawl, Demetri buys Miguel a comic book as a get better present. After Miguel got recovered, he returns to school and Demetri was happy to see him fully recovered. Miguel is concerned when he sees Demetri's broken arm and Demetri tells him how his arm got broken by his own former best friend Hawk. This causes Miguel to confront Hawk about this. While Miguel is arguing with Hawk, he witnesses Kyler drawn a penis on Demetri's cast, this makes everyone to laugh but except for Miguel who is not laughing and feels bad for him, and shows disgust to Kyler. Also, both Miguel and Sam see Demetri and Yasmine kissing and this makes Miguel shocked to see that Demetri is dating Yasmine. During the house brawl, Hawk restores his friendship with Miguel and Demetri after he defects from Cobra Kai. In the end, all three manage to stop Tory and Sam from fighting and Demetri defends Hawk. By the end of the season the trio are training together with the other Miyagi-Do and Eagle Fang students.
Sam is also one of Demetri's best friends. They first meet when Demetri decides to join Miyagi-Do. Despite both being in Miyagi-Do they don't have much interaction. The only time they are shown together outside of class is when the two and Robby are eating at the mall. Although Demetri seems to slightly annoy Sam at times with his antics she is always friendly and supportive towards him, constantly defending him whenever he's threatened as she knows Demetri couldn't defend himself at first.
Early on, Demetri assures Sam they're on the same side against Cobra Kai. When Demetri's science project gets destroyed by Hawk and the two begin a dispute, Sam immediately goes to Demetri's side to give him support, and tells Hawk to back off or he "won't be lucky", showing her care for Demetri's feelings. Sam encourages Demetri and some of the other Miyagi-Do student to get aggressive with the Cobra Kais during a school soccer game, but this earns them detention. After Nathaniel is beaten up by Cobra Kai Sam re-opens Miyagi-Do, with Demetri rejoining. After Demetri gets his arm broken by Hawk, Sam feels tremendous remorse over being unable to help her friend. In the finale, when Sam's attempt to unify Miyagi-Do and Eagle Fang almost fails, Demetri gives an impassioned speech that leads to the dojos successfully merging. He then seems to take charge of the discussion. Their meeting is interrupted when the Cobra Kai students attack the merged dojos. Both Sam and Demetri defend the LaRusso house and win in the end thanks to Hawk's defection. He alongside Miguel and Hawk stop Tory and Sam's fight. They are then seen back at Miyagi-Do, training for the tournament against Cobra Kai. As Sam is the senior student in Miyagi-do, Demetri looks to her for leadership and backs her up when she tries to take the fight to the Cobra Kai students. Even after his arm is broken during the Laser Tag fight Demetri remains loyal to Sam.
Although their relationship is initially strained, over time Daniel becomes a father figure to Demetri. Demetri seeks to join Miyagi-do after getting assaulted by Kreese back at the Cobra Kai Dojo. Daniel starts Demetri's training by having him do chores around the dojo, which Demetri instantly deduces are muscle memory exercises. Once Demetri completes the chores Daniel teaches him self-defense. At first Demetri complains about it because he is not used to fighting. Annoyed, Daniel asks Demetri why he joined Miyagi-Do. Demetri responds that he has been unpopular throughout his life, and now the few friends he does have are joining Cobra Kai and becoming jerks. Daniel then starts to understand him and decides to go more slow on his training that with his other students. Demetri struggles with his training, but Daniel realizes the key is to appeal to Demetri's keen intellect, presenting martial arts as a puzzle to be solved. This finally clicks and Demetri begins to gain both skill and confidence. Overall, despite their rocky start, Daniel had a lot of patience with Demetri and this ultimately paid off.
In season 3 Demetri and Daniel don't interact until later in the season but when he's informed about the fallout of the arcade fight, Daniel is angry to find out that the Cobra Kai students broke Demetri's arm. The first time they are together is when Miyagi-Do is going through basic drills and Demetri is having trouble. A frustrated Daniel tells him that if he doesn't follow what they're learning he will be back in that cast. The last time they are together is the the last scene of the finale, when Miyagi-Do and Eagle Fang have merged and are now training and being run by Daniel and Johnny.
- "After the whole, you know... front wedgie thing... I know what it's like. Sucks to have everyone laughing at you."
- ―Yasmine to Demetri[src]
Demetri expresses an attraction to Yasmine, while the latter mocks him for being a loser. At the party in "Different but Same" Yasmine looks disgusted when Demetri attempts to chat with her. She is initially rude to Demetri, but begins to warm up to him when she sees the dinosaur model he created for their group science project. After Kyler draws a penis on his cast, Yasmine shows sympathy by signing his cast and telling him she now knows what it feels like to be laughed at since the wedgie incident; when Demetri sympathizes with her in return, she looks visibly touched. Later she is caught kissing Demetri by Miguel and Sam, but out of embarrassment she insults Demetri and says she would never date him, although she gives him a flirtatious look and touches his chest before she leaves. Afterward, Demetri tells Miguel and Sam he is "101% in love."
Kyler is Demetri's bully. While at the library with Miguel and Hawk in season 1, Kyler and Brucks come and start bullying them, with Kyler throwing Demetri's backpack in the trash. However, after Miguel defeats Kyler and his gang, Kyler doesn't bully him for the rest of the season, as he is afraid of Miguel. After his arm is injured, Demetri finds himself again being bullied by Kyler. When Demetri accidentally bumps into Kyler in the cafeteria, he throws Demetri's lunch to the bin and the latter draws a penis on his cast and shows it to everyone, causing many to laugh — except for Miguel, Yasmine and the other Miyagi-Do students, who feel bad for him. Later in the hallway, Kyler smacks Demetri and mocks him for the defaced cast.
- Johnny Lawrence (Former Nemesis/Former Co-Sensei)
- Moon (Friends)
- Chris (Close Friends/Allies)
- Robby Keene (Former Friend/Current Enemy)
- Counselor Blatt (Enemy)
- Demetri's surname was originally unknown in the first three seasons, though it fell between A-G. It was later revealed that his surname is Alexopoulos in Season 4's penultimate episode, The Fall.
- Demetri swinging Bert and combining his skills with Hawk is similar to Jet Li using Aaliyah as an aid in Romeo Must Die.
- With the revelation of his last name, it is revealed that he is of Greek heritage.