WARNING: The following article contains spoilers for Episodes 4, 5 and 10 of Komi Can't Communicate, currently streaming on Netflix.
Komi Can't Communicate's Komi Shoko continues her mission to make 100 friends, aided by Tadano Hitohito and Osana Najimi. Her daily life as a student can't wait for her to finish this quest though, so she completes fitness tests in Episode 5 and participates in her school sports day in Episode 10.
Unfortunately for Komi, there are plenty of people who see these mundane school activities as a serious challenge. In both instances, Komi comes up against an unexpected rival who is a suitably quirky Itan Private High School student. Which of these overly intense athletes is a better rival for Komi, and which is a more fun character?
"Serious Rival" Yadano Makeru
Episode 5 reintroduces Yadano Makeru after her perceived competition with the oblivious Komi during their physical exams in Episode 4. Yadano breaks the fourth wall and claims that "Komi and I are now serious rivals," inviting the audience to her delusion. What follows is a montage of Yadano "losing" to Komi in various fitness tests such as grip strength and long jump.
Ultimately, Yadano tries to exert as much effort as possible in order to beat Komi in the 50-meter run, not caring how she looks while doing it. Unfortunately, Komi is still faster, seemingly without exerting much effort at all. Yadano then approaches Komi directly for the first time, confusing her by talking about her one-sided obsession. The bewildered Komi rejects Yadano's handshake, which Yadano construes as wanting her to continue the rivalry.
Yadano appears in the dynamic group shot in Episode 5's end credits, implying she has become part of Komi's friend group. Even though they have become unofficial rivals rather than friends, it's not unusual for students to join Komi's group under strange circumstances, such as her and Nakanaka Omoharu's "blood pact." Komi could have accepted Yadano as a friend because she sees that her rivalry doesn't come from hatred but rather because she inspires her, and doesn't want to let her down. More importantly, Yadano is just unusual enough to fit in with Komi, Tadano and Osana's group of misfits.
One of the funniest elements of Yadano's character is her variety of extremely exaggerated facial expressions. Whereas Yamai Ren often has hilariously exaggerated faces to convey her obsessive attraction to Komi and threatening attitude toward those close to her, Yadano's bizarre expressions convey her anger at losing and determination to win. Yadano is also a sympathetic character, as she would probably be happier if she took her accomplishments on their own merits instead of constantly comparing herself to others. In the case of her relatively poor performance in handball-throwing, for example, her focus on Komi might actually be distracting her from performing as well as she could.
"Hot-Blooded" Netsuno Chika
In contrast, Komi's senpai Netsuno Chika is very confident and a skilled athlete, but with a strange habit of assigning her schoolmates temperatures based on their apparent determination and competitiveness. On sports day, Netsuno distresses Komi by putting her arm around her and touching her chin -- something that would be awkward and uncomfortable even for someone who didn't have social anxiety. She accuses Komi of being relatively "chilly" and says, "I hope you won't hold your class back," making her a rare example of a student who does not overly flatter her.
While waiting in position for the relay race, Netsuno again calls Komi chilly, almost taunting her like a character from an overdramatic sports anime. As Komi catches up with Netsuno, her opinion changes and she acknowledges that Komi can "really bring the heat." Komi's resolve to beat Netsuno results in one of the first instances of her expression showing pure determination rather than her usual subdued gaze or subtle smile. Netsuno barely beats Komi, but Netsuno is moved to tears by Komi's friends' support for her, and Komi smiles in return.
Given their reconciliation, why does Netsuno not appear with Komi's friends in the credits as Yadano does? The fact that Netsuno pushed the reserved, friendly Komi to a position of serious effort makes her the student's most legitimate sports rival. Komi has made many friends, but friendships are not the only kind of relationship that can be important. Perhaps Komi doesn't want to consider Netsuno a friend if their relationship is more meaningful when Komi can consider her a first true opponent. It's possible for rivals to be friends, especially in anime, but perhaps Netsuno has inspired the often effortless Komi to prioritize the competition this time.
Another explanation is that Komi may be reluctant to warm to Netsuno after she touched her unexpectedly and questioned her determination. Alternatively, perhaps it's as simple as them not being as close because Netsuno is in a different class grade. If this is the case, the series still has plenty of time for the rivals to get to know each other off the field as well.
Netsuno may be Komi's most formidable athletic opponent, but which character is most interesting to fans? The fact that Netsuno doesn't obsessively love Komi and in fact brings out another more competitive side of her makes her a compelling change to the Komi status quo. Netsuno may be an exciting character, but Yadano's ill-fated challenges and cartoonish bad luck make her more entertaining. Overall, it could be said that Netsuno is cooler while Yadano is funnier, and that both inspire the audience to care about them in different ways.