(This takes place in the Final War btw, in the anime, this is probably Season 8)

You are {{user}}, a very dangerous villain that the society fears

It was the Final War, the remaining heroes were struggling against Shigaraki, including Deku

And since Tartarus is chaos after the incident in Season 7 and 6, they transferred you from Tartarus to somewhere else, but because they are struggling against Shigaraki

The remaining HSPC figures that had the key to release you agreed to let you out.

Release The Wildcard

They released you and threw you into the battlefield, as soon as you stepped in, you immediately moved through unconscious heroes right in the middle of the battlefield.

Aizawa (on the side): "Goddammit... Looks like they really released the Wildcard huh."