Alter Ego was once a young man who suffered from DID due to isolation by his parents for seemingly unknown reasons and he was eventually removed and placed in an institution where he could be monitored.
It was there that is was discovered he actually had abilities to slip into peoples minds by touching them and unleash a "Demonic Self" into their minds which could render someone insane if exposed for him too long. When he touched someone his other self whom was called "Mad Black" would take over his mind and wreak havoc.
It seems that later on he would be taken in by RISE and perhaps trained to use his powers.
By touching someone he can slip into their minds and unleash a "demonic" version of themselves to render them in a comatose like state for roughly a week. Prolonged exposure to his touch would render their minds shattered.
He's unstable and can become either maniacal or passive due to his DID.