The injuries Bakugo inflicted on himself during the Final Fight arc of My Hero Academia were actually alluded to much earlier in the series during the Final Exams arc. Bakugo’s gloves protect him from overwork by collecting his nitroglycerin-laced sweat as explosive fuel. Bakugo’s character always pushes himself beyond his limits, which eventually causes him to become weak due to overusing his Quirk.
Warning: Spoilers for My Hero Academia’s Final War In the battle with Shigaraki, in My Hero AcademyDuring the Final War arc, Bakugo pushed himself too hard, causing nitroglycerin particles to form in his blood, which exploded throughout his body, causing great damage to himself. While Bakugo appears to be dead, his true fate remains unclear, as Edgeshot was desperately trying to revive him when he last appeared. However, Bakugo’s ability to injure himself in this way was actually hinted at much earlier.
Back in the Final Exam arc of My Hero Academia, Bakugo and Deku were tasked with fighting against All Might, and had to retreat before a specific deadline or leave their opponent unable to fight. The two immediately disagreed on which choice to make, but gradually began working together, to the point where Bakugo actually gave one of his gauntlets to Deku to use against All Might. That leaves Bakugo without support equipment, so when he tries to launch an all-out attack on All Might in chapter 65, he has to do it in a much riskier way.
Bakugo’s gloves protected him from overworking
Bakugo performs his all-or-nothing attack without gloves, a move he admits is risky. The gloves contain sweat reservoirs containing his nitroglycerin, which can then be more safely used as explosive fuel. During the part where Bakugo does this, the veins in his arms can be seen throbbing, showing how much pressure his body is under. The anime (episode 37) actually goes a step further, showing scenes of Bakugo in pain as he performs this explosion against All Might, accompanied by explosion-like flashes of light. Flashes of lightning once again highlighted his bulging veins, much like Bakugo’s seemingly fatal wound during the Final Battle.
Many fans did not like Bakugo’s death scene, as they felt the weakness that caused his downfall was not fully hinted at before, but chapter 65 proves that Bakugo has always had this particular weakness, nearly 300 chapters ago there. Even All Might realized the damage he was doing to himself and ended up knocking Bakugo out in the middle of the exam just so he would stop hurting himself. Otherwise Bakugo could have very easily committed suicide during that final exam, which would have been even harder to explain to the press than his final kidnapping.
Bakugo as a character always tries to push his limits, even when doing so is clearly unsafe, so it’s not too shocking that this flaw eventually happened to him. While Bakugo’s ultimate fate remains unknown, fans can at least realize that his weakness due to his Quirk overuse was indeed hinted at—just very, very early on in the series. My Hero Academy generally does a pretty good job of building up plot points like this, and foreshadowing Bakugo’s self-inflicted injuries is just another way it succeeds at that.