Wiki - Halloween Talismans
Each character that completes either the Journey to the Underworld or the Four Horsemen of the Apocalypse quests 30 times will be rewarded with a Hallowed Effigy. This is a powerful item that goes into the talisman slot.
The stats shown here are an example as they vary for each Effigy. Also, they bind to a character when equipped so anyone wishing to sell or trade theirs will need to do so before equipping it.