My Hero Academia's Katsuki Bakugo established himself as an aggressive, short-tempered character from the get-go. His Explosion Quirk matches his explosive personality. What surprised both fans and the other characters is his strategical intelligence when it comes to utilizing his Quirk in creative ways during battle. He can shoot off explosions in midair to change his trajectory with precise movements to improve his versatility and even use it to fly. From the beginning, Katsuki has proven that his Quirk goes beyond mere explosions, but with little insight into his training and how he got to such a powerful level, there are still a few things that don't quite make sense about his powers.
Explosion Is More Dangerous Than It Seems
Quirks are physical abilities, and thus each one has its own unique limitations that the user needs to surpass if they are aiming to become a hero. When it comes to Explosion, the recoil is barely seen, though during the sports festival, Katsuki stated that even he has his limits. Katsuki enters U.A. High School with a strong grasp on his Quirk as he uses it flawlessly, so it's easy to forget how dangerous his explosions can be to him in addition to his opponents.
In fact, the first time we see some kind of recoil is when Katsuki and Izuku are teamed up for their practical exam against All Might. To gain the upper hand, Katsuki gives his grenadier bracer, which stores his sweat for large explosions, to Izuku. When Izuku used it, he nearly dislocated his arm from the harsh kickback. Additionally, when Katsuki used his explosions without grenadier bracers, a fierce and concerning strain was placed on his forearms. Explosions are definitely dangerous if you're on the receiving end, but firing them off can be equally as dangerous. Though these consequences are hardly seen due to his training, they still very much exist.
Bakugo Is Immune To His Own Explosions (For Now)
Speaking of consequences, with such an eruptive Quirk, it's a wonder how Katsuki has come so far without obtaining permanent damage, unlike Izuku who adorns several gruesome scars from his own Quirk. Explosions are destructive and very loud. While Katsuki often creates powerful explosions on a regular basis, some fans have already entertained the idea that his Quirk will cause him to become deaf in the future.
With the nature of his Quirk and without any kind of earplugs to his costume, this seems plausible. Furthermore, although nitroglycerin is a smooth chemical, Katsuki ignites explosions from his palms, yet he doesn't have calluses or scars. Despite wearing gloves as part of his costume, he used his Quirk most of his life likely without them and does not hesitate to let his hands spark without gloves.
Despite Science, Bakugo Isn't Affected by the Cold
Katsuki's Quirk comes from nitroglycerin in his sweat, so the more he sweats, the greater his power. However, when placed in cold climates he doesn't seem to have a problem creating explosions. In the sports festival's final round, Katsuki had to face off against Shoto, who primarily used ice. Despite being surrounded by heaps of glaciers which effectively dropped the temperature around them, Katsuki had no trouble in attacking. Since his Quirk is heat-based, theoretically the cold would put him at a disadvantage. Even his winter costume provides extra warmth to keep him sweating in the cold, yet this conspicuous limitation due to the prerequisite of his Quirk is never seen as an obstacle.
Bakugo Never Runs Out of Sweat
Since Katsuki's sweat serves as the fuel for the explosions, it seems likely there would be a limit to how much his body can sweat out. The larger the explosion, the more sweat is required to ignite it. During the training camp, Katsuki's training to improve the power of his Quirk involved immersing his hands in boiling water to enlarge his sweat glands. Although he underwent rigorous training to increase his ability to produce sweat, there should be a limit to the number of explosions he can create before exhaustion takes over. Regardless, Katsuki is definitely one sweaty boy.
Bakugo (Somehow) Never Combusts
While Katsuki can ignite his sweat to produce sparks and explosions, it is all fueled by nitroglycerin, which is a highly explosive and unstable chemical. While it is often used in concentrated form for dynamite, even on its own, a small movement, impact or friction can make it spontaneously explode. Though Katsuki doesn't sweat straight nitroglycerin and it is instead induced with his sweat, the chemical is still very much present judging by the powerful explosions and, theoretically, should be an issue living day-to-day life. While Katsuki can activate his Quirk at will without issues, he is shown to have a strong handle on his explosions. They never go out of hand and he doesn't take extra caution when participating in certain activities. For example, the heat from being in a hot spring during the training camp should've set off an explosion.
In real life, sweating nitroglycerin would be a serious health concern, but Katsuki takes no steps to nullify it should the need arise. In the first episode of the anime, when he was being held captive by the sludge villain, pro heroes couldn't get to him because he had carelessly used his Quirk and created various fires, increasing the danger of the situation. Katsuki has most likely trained to prevent these sorts of accidents from happening again, but it's still a mystery why he doesn't take extra precautions to avoid combusting when he sweats after a grueling training session. Despite the natural properties of nitroglycerin, even if his Quirk is somehow stable, his personality is not.
