WARNING: The following contains spoilers for My Hero Academia Chapter 347, "Inflation” by Kohei Horikoshi, Caleb Cook and John Hunt, available now in English from Viz Media.
Shigaraki Tomura revealed his terrifying new abilities in My Hero Academia Chapter 346, stunning the heroes and restructuring the battle to a more equal standing. Now in Chapter 347, he explained how his body augmentation works and, in doing so, challenged the heroes to a fight for their lives.
Even though teleporting Shigaraki to UA gave the heroes the element of surprise for a brief moment, attacking the villain without knowing the full scope of his powers gave him the perfect opportunity to counterattack. Ever ready for a fight, Mirko leaped right for Shigaraki but was pushed away by a gigantic new appendage Shigaraki had manifested that was made up of countless fingers. Even more mystifying, his new arm continued to grow -- despite still being under the effects of Erasure.
Eraserhead confirmed Monoma had activated his Quirk perfectly but he needn't have, as Shigaraki went on to explain that his new ability was not a Quirk at all, and thus could not be Erased. The villain called it simple growth, likening it to processes that happened naturally like his hair and nails growing out. He called it the next step of human evolution and implied that the species as a whole would have to evolve in a similar nature as him if it were to conquer the Quirk Singularity.
Understandably, this new development troubled the heroes but as they considered the information Shigaraki had given them, their situation got even more dire. They couldn't write off the possibility that Shigaraki could activate Decay throughout his continuously growing hands so even though Monoma's Erasure could do nothing to stop their spread, he had to keep the Quirk activated on Shigaraki. If Erasure's effect wore off for even one second, all of UA -- on which they stood -- would instantly begin to crumble.
When MHA protagonist Midoriya Izuku contacted the UA team, he requested a Warp Gate so he could instantly return to his original post. Even with One For All, victory against Shigaraki's new powers wasn't assured but he was counting on teamwork with the more experienced Pro Heroes to settle the fight. Unfortunately, this reunion wasn't meant to be. A Warp Gate for Midoriya would require Monoma to deactivate Erasure since he couldn't use two Quirks at once, and the heroes can't gamble losing everyone at UA just to bring Midoriya to the scene.
Eraserhead told Deku that he'd have to return to UA on his own. In the meantime, the heroes currently on the scene will have to battle Shigaraki on their own. None of them are quite on Deku's level but they should be able to put up a worthy fight. The offensive team consists of three of the top 10 Heroes; Best Jeanist, Edgeshot and Mirko along with three of UA's brightest stars, Amajiki Tamaki, Hado Nejire and Bakugo Katsuki. This all-star team may be severely handicapped but they don't seem ready to give up without a fight as My Hero Academia continues.
