Warning! Spoilers for Chapter 160 of the My Hero Academia manga below!
The heroes of My Hero Academia are still dealing with the fallout after the charge of Overhaul and the Eight Precepts of Death's home base, and now that there's a power vacuum, the villains have gotten fiercer.
As Overhaul and his fellow yakuza eventually fell to the efforts of Izuku, the phasing hero Mirio, and their Quirk-erasing teacher Aizawa, he was being escorted to the nearest hopsital and police station to treat his injuries and pay for his crimes. But in the middle of the highway, the villain Tomura Shiragaki and his League of Villains were there waiting for him.
The League of Villains, who had refrained from unnecessary action up to this point, attack the police detail. The Sand Hero Snatch had been lying in wait, as his granular sand body was the perfect opposite to Tomura who could only decay what he could get a good grip on. But the League was thinking ahead as Compress, the villain whose quirk compresses anything he wishes into tiny spheres, uses his power to summon giant rocks to derail every police vehicle.
As Tomura and Compress stand over the restrained Overhaul, they not only steal Overhaul's quirk-erasing serum but completely remove both of Overhaul's arms. With this, Overhaul's spirit is broken and Tomura completely revels in how much he's making him suffer.
Before the final events of My Hero Academia's "Internship arc", Tomura and Overhaul had entered an uneasy alliance as Overhaul seemingly had the upper hand on the League of Villains. Overhaul's group had been victorious in every confrontation the two groups had up until this point, and it seemed like Tomura was willingly working with Overhaul in order to prevent further damage to his league. He had even lent two of his villains for their final operation, but with this revelation, Tomura had this ultimate betrayal all along.
Although the final battle in My Hero Academia's "Internship" arc had the biggest spectacle of the series yet, this latest bit of brutality is the darkest tone the series has ever approached. With Tomura's final vow that his League of Villains will be the next imposing threat, the tone of My Hero Academia is sure to change going forward.