Demetri hasn’t always been one of Cobra Kai’s strongest characters, but he becomes a much better and more fully-formed character in season 3. While still more of a side character to some of the more central teens like Miguel, Robby, and Sam, Demetri has played an increasingly significant role in the story as the series has progressed. His season 3 arc is his best yet, as it finally starts to break out of the stereotypical writing that’s held him back so far.
In Cobra Kai’s first season, Demetri doesn’t do all that much of importance. He and Hawk befriend Miguel early on, but Demetri stays mostly on the sidelines, choosing not to train in karate and serving mostly as comic relief. He gets much larger part in season 2 as Miyagi-Do Karate’s third official student. He builds strength and confidence slowly over the course of the season, eventually managing to fight off his former friend, now-bully Hawk in the finale’s school brawl.
While Demetri’s role grows through the first two seasons, he remains plagued by the same central problem - clichéd writing. While Miguel and Hawk feel multi-dimensional and unique in their motivations, Demetri doesn’t really get past the tropes of referencing sci-fi at comically inopportune times and using words that are bigger than other people’s words. He certainly grows, but his writing doesn’t allow for the expanded space his arc demands, which finally changes in season 3 when he becomes crucial to its ending.
After his impressive victory over Hawk in the Cobra Kai season 2 finale brawl, Demetri’s confidence and popularity at school skyrocket. This doesn’t change anything about his core behavior or personality, but it does give his character room to stretch. Now that he’s a competent fighter and sort of dating Yasmine, his quirks feel less like lazy tropes and more like fun, distinct character traits. Season 1 was fun largely because of Miguel’s twist on classic stereotypes - a “nerd” who actually carries himself with poise and confidence from the start. Demetri has now become a more interesting character as the opposite - an increasingly popular kid who still acts like a dork.
Cobra Kai’s younger characters have always been a huge part of the show’s success, largely because of how so many of them are layered with complex traits and motivations. Demetri fell short of that in the early seasons, but he’s certainly coming into his own now. His renewed friendship with Hawk should be of particular interest next season, as it will give both characters room to learn from each other after their falling-out. As the dojo war with Kreese ramps up, Demetri could play an even larger role in Cobra Kai season 4.