Signal is the gatekeeper of the Kyrie Gate at Bifrost Bridge. He uses a method whereby a pipe is used to verify the identity of a person who wants to cross the bridge. His former name was Camus and used to be a Letter Bee. Twelve years prior, he and his other two brothers were aboard the government airship when it crashed on the Day of the Flicker. He was a substitute in place of Largo Lloyd and was one of the 6 people who survived the incident.