History
Little has been revealed about Riot Act past. He used to be fairly harmless criminal, who spent some time in Blackgate Prison. Everything has changed, when he met a Joker, during a prison transfer. Inspired by him, he decided to become another costumed criminal, causing chaos and destruction just for fun. He was eventually caught and sent to Arkham Asylum.
Some time later, he managed to escape from Arkham and decided to deal with Batman. In order to draw his attention, he stole a big truck and started to ride on the busy streets of Gotham, causing severe damage and injuries among civilians. He was finally stopped by Robin, who caught him without major problems and left for authorities. After that, Riot-Act was likely, send back to Arkham.