The following contains spoilers for Episode 13 of Komi Can't Communicate, "It's Just the Arrival of Winter," now streaming on Netflix.
At its core, Komi Can't Communicate explores various forms of social anxiety; this is even reflected in the series title and the titular heroine's name. While Shoko Komi experiences an extreme type of social anxiety that manifests in the form of a communication disorder, the other characters also explore the myriad of ways it manifests itself. In the case of protagonist Hitohito Tadano, his social anxiety causes him to participate in avoidant behaviors, while Himiko Agari's manifests in the form of constant panicking.
Two more characters who explore different forms of extreme social anxiety are Makeru Yadano and Omoharu Nakanaka. For Yadano, it manifests into an obsession with winning, while Nakanaka's comes in the form of her being a chūnibyō. Komi Can't Communicate Season 2 debuts a new character, Makoto Kotai, who explores another facet of extreme social anxiety, but there is something different: he has Komi's paralyzing anxiety coupled with Tadano's avoidant behavior.
When Katai introduces himself in Episode 13, he clarifies that he is not a transfer student; he has attended Itan Private High School since the start of the school year but got sick during the first week of class. Even after he recovered a week later, his anxiety prevented him from attending and he kept postponing his return in the months leading up to the winter semester. During his absence, Katai bleached his hair and started a bodybuilding program in an effort to develop a tough image that would intimidate bullies.
The day Katai finally shows up to school, his appearance immediately intimidates his classmates, who mistake him for a thug. Though he clarifies through his internal monologue that he's actually a normal guy who is extremely shy, the way he tries to leave a good impression doesn't yield the desired effect: when he smiles at others, he comes off as threatening rather than friendly. He is unaware of this, of course, since his mind is busy trying to overcome his social anxiety.
In the first few seconds he appears on screen, it's immediately established that Katai has much in common with Komi. Like the titular heroine herself, Katai is judged by his physical appearance and his anxiety is easily mistaken for unfriendliness. When it comes to interacting with the other students, Katai also struggles to speak a single word, even after he meets someone like himself -- in this case, Komi. In the scene where he attempts to introduce himself to her, Katai becomes paralyzed with fear and can't bring himself to actually talk to her. Amusingly enough, this ends up triggering Komi's own anxiety.
After observing Komi and Katai stare at each other in fear for a while, Tadano figures out Katai also has a communication disorder and takes initiative by talking to him. This catches Katai off guard, but he is ultimately receptive. When Tadano offers to give him a tour of the school as a way of breaking the ice, Katai accepts and immediately takes a liking to his new friend. Komi then recognizes this gesture as the same one Tadano used on her when they first met.
This realization immediately makes Komi feel uneasy, especially since she herself has not yet caught on to the fact Katai also has extreme social anxiety. Interestingly, Katai's interpretation of Komi's behavior is just as wildly different. When they were staring at each other, the fact that neither looked away made him believe he was making progress with eye contact -- something he struggles with.
After Tadano invited Katai to tour the school with him, Katai further hypothesized that Komi must be some kind of communication master, not knowing she too has extreme social anxiety. Even more amusing: Katai reveals he's been reading the same communication book as Komi.
While Katai and Komi are off to an awkward start in Episode 13, his introduction creates interesting story opportunities for Komi. As a character who shares common traits with both her and Tadano, it'll be interesting to see how Katai and Komi will get along once she becomes aware of his extreme social anxiety and communication disorder. If Tadano starts spending more time with Katai like he did with Komi in Season 1, will she be accepting of this new friendship -- or will she see him as a rival for Tadano's affection?