The Red Chain is an unobtainable item (though it can be through a cheating device) recreated by the leader of Team Galactic, Cyrus, in order to control Palkia and Dialga. The chain's condition after the events atop Mt. Coronet is unknown.
In the anime, it seemed to be some kind of glove with a red jewel that glows when Cyrus takes over Uxie, Mesprit, and Azelf.
Trivia
- Originally, it was supposed to be held and used for a purpose in the storyline in Diamond and Pearl.