The following contains spoilers from chapter 272 of My Hero Academia. You have been warned.
Now that Tomura Shigaraki is awake, we finally got to see a small taste of his new power. For now, all we got to see was his augmented Decay quirk and none of the quirks he got from All For One. Even so, the power of that one quirk was more than enough to cause all-out chaos on the superheroes. After he woke up, Shigaraki wasted no time using his Decay quirk to disintegrate the hospital, the surrounding area, and all heroes present. A lot of superheroes died by Shigaraki’s hand in a matter of moments. The whole scene looked like something from an earthquake as the superheroes frantically tried to save as many people as they could while desperately trying to escape Shigaraki’s wrath. Those who failed to escape were turned to dust. As the superheroes ran for their lives and evacuated the area, they tried using their quirks to stop Shigaraki’s rampage, but it was useless as his Decay quirk disintegrated everything in its path. While this was happening, Doctor Ujiko laughed maniacally at the heroes, saying all their efforts to stop Shigaraki have been in vain. Meanwhile, Izuku Midoriya could sense what was happening long before the city disintegrated and he started using One For All at 45%, which is the highest he has been able to activate on his own so far. In the epicenter of the destruction is Shigaraki himself, laughing with joy while claiming a hero’s cape as his own. I think we are about to see the first round of Izuku and Shigaraki’s grudge match. I can imagine it being similar to when Batman first fought Bane, which resulted in Batman getting his spine snapped in two. Overall, this was a satisfactory taste of what the new and improved Tomura Shigaraki is capable of and I look forward to seeing what other quirks he has gained from All For One in the next chapter.