This article is about the Key in its original form, see Dawn Summers for information on the being into which the Key was transformed
- “The Key is the link. The link must be severed. Such is the will of God.”
- ―Lithany of the Knights of Byzantium[src]
The Key is an ancient mystical energy with the power to unlock the gates between all existing dimensions. Who, when or why it was created is unknown, though in the XII Century, the Order of Dagon was founded by Tarnis in order to protect it. Meanwhile, the Knights of Byzantium sought to destroy the Key so its destructive power would never be unleashed.
After the events of "The Gift", it is heavily implied that the Key no longer exists, and Dawn is a true human now.
- No Place Like Home (Only in flashbacks)