WARNING: The following contains spoilers for My Hero Academia Chapter #309, "Can't Be A Child Anymore,” by Kohei Horikoshi, Caleb Cook and John Hunt, available now in English from Viz Media.
In My Hero Academia Chapter #309, Deku debuted an ominous new outfit that’s starkly different from many of his previous hero costumes. This new getup might be more likely to frighten the average citizen than reassure them of a hero’s presence.
As Deku continues learning to use One For All in more flexible ways, his costume has evolved with him, although interestingly, it's never strayed too far from the theme of his very first suit. But this new design has a darker feel than before.
Deku's outfit bulked up quite a bit when he upgraded to Costume Gamma, which featured braces to support his weakening arms and steel soles that further complemented his new Shoot Style. He also added support gloves, designed by Mei Hatsume, along the line. Those new gloves allowed Deku to use the pressurized winds he showed in his match against Shoto on a smaller scale, but with much greater precision.
His latest costume, as unnerving as it is, looks more like a callback to his very first jumpsuit. It does have a few unique features, both in functionality and aesthetics, that portray just how far he’s come in his journey to becoming the world's greatest hero.
The new suit is a near-complete overhaul of Costume Gamma. Deku does retain his steel-toed boots, however, implying he hasn't totally abandoned the Shoot Style. A new addition to this suit is the mid-gauntlet compression support items, metal bands that cover his entire forearm -- similar to the item Melissa Shield gifted him in Two Heroes. The mid-gauntlets reinforce Deku's whole body, allowing him to go past his allowable limit of 45% of One For All. They still can’t withstand 100% of his power, however, so Deku has to be careful.
Deku’s face is hidden by a mouthguard and his signature bunny-eared mask is pulled forward, although it looks a little worse for wear than it ever has. The final new addition is Gran Torino’s battle-worn cape, which he wears like a shawl around his shoulders. The full effect gives Deku a more menacing aura. The tattered clothes and unpolished appearance give him a close resemblance to the hero killer Stain.
Deku's costume has always reflected the kind of hero he’s aiming to be. Back when it was “one that saves everyone with a smile,” the All Might influence was impossible to miss. Later costumes continue to reflect the person Deku is becoming, as the new additions help form his own identity. His goals changed once again after the Paranormal Liberation War, and now he aims to recapture as many escaped villains as possible while keeping his identity a secret.
This new anonymity also means he won't get any credit for captured villains and although he’s working with top heroes, he’ll still be classified as a vigilante. It's an arrangement that perfectly fits Stain’s view of what a hero should be like.
Deku's new costume is perfect for this new goal. The mid-gauntlets allow him to take on even stronger villains like Muscular and the always-on mask will protect his identity. Deku’s “vigilante” suit hasn’t been shown in action much yet, but he's clearly more powerful than he’s ever been. It may even hide a few more surprises to be revealed in future My Hero Academia chapters.