Clack and Keith are the main antagonists in the second Prince of Tennis movie: Battle in the British City. Clack is a street tennis group based in England that is made up of tennis players that have been kicked out of tennis schools. All members of Clack are banned from entering and competiting in official tennis tournaments. The leader of Clack is Keith, and there are approximately 20 members altogether. Xiu Ling, Keith's doubles partner and possibly former co-leader, was the reason behind the formation of Clack.