The following contains spoilers for My Hero Academia Season 5, Episode 6, "Foresight," now streaming on Crunchyroll, Funimation and Hulu.
Fumikage Tokoyami may not be My Hero Academia's brainiest hero, but the combination of his dark aesthetic, brooding personality and Quirk with a separate consciousness makes it seem very unlikely that one could successfully pull the wool over his eyes. It just so happened that when Kuroiro Shihai completely outwitted him, he took advantage of these very traits of Tokoyami. Here's how Class 1-B's Scheming Hero pulled the deception off.
During the UA first years' Joint Training exercise, Classes 1-A and 1-B were split into even teams and pitted against each other. As luck would have it, the team facing off against Tokoyami's included a student who was almost his perfect counterpart: another hero shrouded in darkness and with a Quirk to match. Kuroiro's Dark Quirk allows him to enter and merge with any black objects and travel within them, as well as move them -- but only if the object was originally capable of movement.
Given his relatively weak Quirk, Kuroiro knew he couldn't rely on it alone if he wanted victory for his team. Before the match even started, therefore, he'd thought of a plan to incapacitate Tokoyami and his powerful Dark Shadow, implementing it as they were heading to the training grounds. He approached Tokoyami and suddenly declared they were just like each other. He claimed they shared a destiny, leading Tokoyami to believe Kuroiro would be gunning for him the entire match. Their seconds-long interaction proved to be the 1-A team's undoing.
When the match began, Tokoyami released Dark Shadow, leaving his independent Quirk to scout ahead for information on his team. Despite knowing the specifics of Kuroiro's Quirk, Tokoyami never imagined Dark Shadow would be susceptible to his control. Evidently, Class 1-A was not the only group that had made progress with their Quirks. Kuroiro possessed Dark Shadow and, when he returned to Class 1-A, wasted no time in completely disorienting the team with Tokoyami's Quirk.
At this point, all signs still pointed to Kuroiro having a personal vendetta with Tokoyami. While Class 1-A rallied around him and prepared to defend their heaviest hitter, Kuroiro's attention was somewhere else entirely. Having successfully achieved his aim of misleading his opponents, he turned his sights on Aoyama Yuga, snatching him up by his cape and racing toward the rest of his teammates.
Team 1-A lost the upper hand at that moment, and although they came quite close to regaining it several times, the match ended in their class' singular loss for the exercise. Kuroiro's strategy, while a bit underhanded, was exactly what Class 1-B needed to win their match.
Apart from his airtight plan, keeping his Quirk's upgrade a secret showed foresight one would usually expect from Pro-Heroes like Nighteye and Eraserhead. Kuroiro (and his close friend, Kinoko Komori) showed that My Hero Academia's heroes don't necessarily have to be paragons of moral upstanding if it interferes with their end goal of stopping villains, proving why he deserves the nickname Scheming Hero.