The following contains spoilers for Chapters 351 and 352 of My Hero Academia by Kohei Horikoshi, Caleb Cook and John Hunt, available now in English from Viz Media.
My Hero Academia has an especially large cast of characters compared to most shonen series. While that helps make the story feel more populated and diverse, it also has the unfortunate side effect of having many characters fall through the cracks and fade into obscurity all too often. This unfortunate fate has befallen many throughout MHA who might have otherwise been fan favorites, and it's repeating itself in the final arc's first cour.
The latest My Hero Academia manga chapters have focused on Todoroki Shoto's fated final battle with his estranged brother Dabi. Since mastering both the ice and fire aspects of his Quirk and becoming invulnerable to flame, Shoto was the obvious man for the job. Of course he still couldn't be sent to confront the villain alone, so he was escorted by a group of student and Pro-Heroes alike, including Iida Tenya and Endeavor's trusted Flaming Sidekickers, Kido, Onima and Burnin.
While the original plan was for all the heroes to confront Dabi together, the villain's murderous flames quickly rose to a temperature that would've been fatal to ordinary folks. The other heroes were forced back, but the Flaming Sidekickers bravely declared that they'd withstood worse and were ready to engage Dabi whenever Shoto was. At that point, all signs pointed to them taking down Dabi as a team -- but that idea was quickly discarded when he made his first move.
By taking the initiative, Dabi skewed the battle in his favor for a moment and the Flaming Sidekickers were left scrambling. It quickly became a firefight involving just the two brothers, and the promises of support came to naught. They remained irrelevant until the very end of the battle, when they managed to jump in the way of an attack aimed at Shoto. Their tenacity, although short-lived, gave him enough time to charge up the Coldflame that ultimately took Dabi down.
Although the Flaming Sidekickers were never main characters to begin with, it's a little disappointing that My Hero Academia might end without some exposition on Endeavor's most trusted crew. One of the ways MHA's Pro-Heroes assert their individuality is through their uniquely named supermoves, but the Sidekickers never got that much of an opportunity. They were certainly brave during Shoto's fight with Dabi, but it hardly counts as an opportunity to display why Endeavor placed so much trust in them.
Especially concerning is Burnin's treatment, which continues My Hero Academia's infamous trend of sidelining its female characters after singular battles. They show immense promise at the beginning, then are invariably injured or taken out of the action without any opportunities for character growth.
Burnin' never got the chance to stand out, and in the manga hasn't even had a dedicated moment to explaining her Quirk. (Blazing Hair allows her to fly and grab the flames off her head and toss them as projectiles.) She might have been MHA's last chance at overturning how one-dimensional many of its women are perceived, but unfortunately, that doesn't look like being the case.