The Relic is an item obtained in Devious Minds. Players doing the quest unwittingly help an assassin reach Entrana, at which point he slays the monks who were protecting it and steals it. After the theft, the High Priest tells the player to inform Sir Tiffy Cashien of the events. Sir Tiffy tells the player that he will be "in touch" later, hinting towards The Temple at Senntisten. It appears to have a star of Saradomin carved on it.
The player later on receives the relic back from the assassin to give to Azzanadra during The Temple at Senntisten. If the player tries to take the relic to the High priest on Entrana instead of taking it to Azzanadra, the High priest yells "Look out, he's got a boulder!" The player is then knocked out and wakes up on a boat at the Port Sarim docks.
After The Temple at Senntisten, Azzanadra will tell you that the relic is a catalyst for holy power and is pretty useless by itself. He says that it causes the Barrows icon to give off a larger amount of holy energy, which is then amplified using Frostenhorn to be able to communicate with Zaros. He also says that because the Saradominists have carved their symbol on it that he would want to be far away from Saradominist lands once Zaros sees it.