In Chapter 369 of My Hero Academia, Deku finally employs all seven of his Quirks, but his tenacious strength carries a secret danger.
In Chapter 369 of My Hero Academia, Deku has taken over command of the battlefield, but the heroes aren't yet completely safe. Even the portion of All For One living inside Shigaraki Tomura at UA might not be as lost as it seems. All For One still has several significant generals working independently of him.
For the time being, the evil foe is more than enough to be overpowered by Deku's released might, but activating Gear Shift's full potential entails grave danger.
Deku's use of One For All has always been risky.
There were always dangers associated with the gift of One For All. Aside from the fact that Deku would inevitably encounter All For One due to inheriting the Quirk, abusing its power would always result in harm. When Deku overused his body, the part of his Quirk that was affected would become bloody and bruised, rendering it completely useless unless Deku was prepared to endure excruciating pain. One For All's strength was far greater than what Deku's body could handle at the time.
Deku once more had to set limiters on a new power to use it safely when Blackwhip appeared. In this situation, the Quirk not only made him physically uncomfortable, but he also ran the chance of Blackwhip spiraling out of control like it did during the MHA's "Joint Training" arc. Like with One For All, Deku took his time to understand how the Quirk operated before considering it a trustworthy weapon in his armory.
How Risky Is Deku's New Gear Shift Quirk?
The current situation in My Hero Academia has made Deku abandon his logical approach to learning Quirks. He hadn't used Gear Shift before, and a full-scale war wasn't exactly the best place to practice. He just knew that the Quirk would allow him to change the pace of anything he touched, even himself, but Deku is already a master at using it. It appears that his years of intensive practice with Quirks and research have paid off.
Deku was tempted to utilize Gear Shift to hasten his voyage to UA, but the Quirk's first wielder, One For All's second user, warned him against it. He advised the young hero to hold off on using his Quirk until a good time since he was concerned about the fallout that would occur five minutes after Deku turned on Gear Shift on himself. According to his description, Gear Shift should only be used as a last option. The moment finally arrived when Deku was brought face to face with All For One.
The Second reminded Deku once more of the dangers of using his power when he engaged All For One in combat. He said that after activating Gear Shift, Deku had a five-minute window in which to defeat All For One, and even that is predicated on him not making an error sooner due to the strain of simultaneously controlling seven inherited quirks. Deku may appear unbeatable right now, but his fight with All For One is just as much a race against time as it is a physical confrontation. Although the cost of going beyond this limit has not yet been made clear, it is clear from Deku's eagerness that he has no interest in learning it.