My Hero Academia is a love letter to both the superhero genre and shonen manga, including many popular tropes of both. This includes the idea of sidekicks. Even the strongest heroes can't do everything alone, not even All Might himself. With his incredible power of One For All and his dazzling charisma, the Symbol of Peace understands that he needs support staff, and he is rather picky about who he teams up with.
Who has worked best with All Might in the past, and which heroes are best-suited for being his sidekick in the future?
All Might's Best Sidekick: Sir Nighteye
All Might used to have a sidekick by the name of Sir Nighteye, a patient and bookish man who adored All Might with all his heart. In a way, Sir Nighteye was like Izuku before Izuku himself came along, but rather than a student-teacher relationship, the two fellows were simply business partners who made the most of their respective talents. In these days, Sir Nighteye was the brains of the outfit, using his advanced intellect and the power of his Foresight Quirk to plan out All Might's missions and outmaneuver villains of all shapes and sizes. Later, when All Might suffered serious wounds from All For One and had a falling out with Sir Nighteye, his former sidekick went it alone and founded his own hero agency.
Sir Nighteye was All Might's best sidekick because he complimented, rather than matched, All Might's strength. Finding someone else with the same power as All Might would be both unlikely and redundant, but finding someone who can offer logistical support is extremely helpful. The likes of Sir Nighteye can run the books and formulate advanced strategies, effectively pointing All Might's strength in the right direction. A good analogy may be a sniper/spotter team, where it may be the sniper who pulls the trigger but the spotter is responsible for tracking the target, gauging wind direction and speed, noting the terrain and basically everything but shooting. Sidekicks like Sir Nighteye are valued for unique skills, not necessarily powerful ones.
David Shield & Naomasa Tsukauchi, All Might's Agents
Some of All Might's best "sidekicks" aren't even costumed heroes at all. David Shield, for example, is an American researcher who builds support items to enhance the performance of heroes such as All Might himself. David is happy to blend into the background in this role, and he was honored to have the California Smash named after his home state. David idolizes All Might and gives him moral support on top of everything else, proving that even ordinary men like him can make a real difference.
Another great non-costumed "sidekick" of sorts is Naomasa Tsukauchi, a Japanese detective who can sniff out any lead on villainous activity and dig in deep. This intel-gathering work is vital for helping heroes like All Might find the location and activity of insidious criminals. Before a villain eats a Smash attack, All Might has to know where to even find the villain.
Possible Future Sidekicks for All Might
Who else could fulfill the role of All Might's sidekick? Shota Aizawa, known as Eraser Head, could easily take Sir Nighteye's place, given his incredible street smarts and talents for espionage and tracking. Aizawa's Quirk Erasure could also prevent villains from using their own Quirks to take hostages or threaten crowds of civilians, preventing villains from gaining the upper hand against All Might's legendary strength. While Aizawa is also capable of fighting as a hero himself, his talents would make him a deluxe-caliber sidekick for an even stronger hero, if it came to that, and Aizawa wouldn't be too proud to say no to All Might.
Mei Hatsume is a U.A. student who promises to be an outstanding sidekick one day since her combat skills are minimal but her gadgets are outstanding. Mei's Quirk is Zoom, allowing her to use her eyes like telescopes or microscopes, and thus tinker with tiny, delicate mechanical parts with ease. That, combined with Mei's natural talents and enthusiasm, means Mei can invent just about any item for a hero, as Izuku and Tenya Iida can attest to. Mei's inventions can augment a hero's natural abilities, protect them from harm, allow them to communicate over a long distance, or negate the downside of their Quirk. All this makes Mei the definition of a superhero sidekick.
Momo Yaoyorozu is another trainee hero who may be best off supporting a frontline fighter rather than doing the fighting herself. Like Mei, Momo is a brilliant girl who's good with gadgets and items, but rather than invent new weapons or armor, Momo can create nearly any non-living object from her skin to aid injured civilians or capture low-level heroes. Suppose Mei was a sidekick to All Might or a similar hero. She would leave the strongest foes to the main hero, while she would capture the stragglers with her Quirk and prevent them from calling over villainous reinforcements or escaping with stolen items. Momo can also aid the main hero with her capacity to support civilians with bandages, tents, gas masks and far more.
Even All Might, for all his amazing power, is sometimes too slow to save everyone. He can't be everywhere at once, so having a sidekick helps him catch anything issue that falls through the cracks and save countless lives. Sir Nighteye was his best sidekick so far, but many other heroes would also be well-suited to take on the responsibility in the future.