Decay (崩ほう壊かい Hōkai?): Tomura's original Quirk allows him to disintegrate whatever he touches with all five fingers. It will take effect whether the target is organic or not. The disintegration spreads quickly and will spread through the victim's whole body if they don't amputate the decaying body part. His Quirk can even spread beyond what he's touching, allowing him to disintegrate large groups of enemies instantly.

Because the Quirk has to touch a solid object in order to be activated.