Set before the events in Kohei Horikoshi's main series, the spin-off Vigilante My Hero Academia Illegale Not only did he explore the pasts of some of the characters we've seen like Endeavor, but he introduced us to the vigilantes and new villains, including the mysterious Number Six, the main antagonist.
In the last few chapters we saw how powerful number six actually isthat did not hesitate to hide some very specific aspects. Indeed, if his name had already intrigued readers, the fact that he could wield a power that once belonged to All For One would have done nothing but fuel numerous theories that appear to be confirmed in the most recently published tables.
After a devastating attack by young Endeavor, to say the least: Number six is right across from Koichi, The Crawlerand although his body is still covered in burns and flames, the villain doesn't care at all. As he himself explains, his body is able to withstand this damage and absorb it, so far as to say that it is the result of an artificial project clearly referenced Nomu, genetically modified people.
It appears that the Crawler's arrival thwarted his evil plans and that all the actions he took were a way to escape the lies that characterize his past. Recall that chapter 84 paid homage to Batman and Koichi pushed his limits again.