The Terror is a supervillain who operated in The City.
Fifteen years ago, The Terror used a weaponized version of syphilis to destroy the eyes of the Flag 5. He then had his henchmen kill the Flag 5 in front of a young Arthur Everest – who had just lost his father when the Flag 5's aircraft crashed on top of him. To top it off, The Terror stole Arthur's ice cream.
A year later, The Terror was killed by Superian. The site of their battle became a crater, and The Terror was only identified when they found his teeth embedded in the crater walls.
Despite The Terror's death, Arthur believed that he was still alive, having gone underground to control all the crime in The City.