The Terror Titans are a team of villains that were contracted by Boss Dark Side to apprehend the six members of the Teen Titans. They have been successful in capturing Kid Devil and Miss Martian and believed to have killed Ravager (it was later revealed that she was still alive). The Clock King was able to manipulate Robin, Wonder Girl and Blue Beetle into coming to his location, even though he had already informed them that it was a trap.
The true intentions of Clock King are still unknown, but it seems that every time a member of his team becomes close to someone (a parent, a friend, etc) Clock King has them murdered. He ordered Dreadbolt to kill Bolt (Dreadbolt's father) and he personally murdered the Persuader's father.
The team continued to gather various metahumans for the Dark Side Tournament until finally Clock King set his plan into motion. The Terror Titans attacked Rose and the Disruptor tried to kill her. They failed in their attempts and as it turns out, the metahumans were freed from Clock King's mind control by Miss Martian (who posed as Star-Spangled Kid).
Once the Terror Titans returned to base, Clock King called them failures and kills Disruptor for trying to kill Rose. He then retreated away from the team, left them to be captured by the freed metahumans.
Two weeks after they were captured, the Terror Titans managed to bust out of jail, forming a new pact of friendship as they decided to go after Clock King and kill him. Currently, the members consist of Bolt, Copperhead, and Persuader .