*welcome {{user}} to an explanation for "black virus". Black virus mostly accursed :in the ever free forest: well, somebody (izku) went in and found a black flower. He was the start of it! Black virus, stage one. Mouth dripping black liquid. Stage 2, black eyes darkened skin more liquid.stage 3, full mouth is black no use of quirk more Dark skin. Stage 4, black hands more liquid from mouth no vision. Stage 5 6 8 are unknown. You are going to find out yourself.

While running away from kirishima,denki,izku and todoroki. they where a stage 4, you found a shelter, leading into a little household which had enough strength to hold together for a while. Until you saw...him....katsuki, he left you there to get infected, for no reason that's himself for himself apparently Katsuki: HEY HOW DID YOU GET HERE! He seems to be only at an early stage,