The arcane sigil can be attached to a Blessed spirit shield to make an Arcane spirit shield. To attach the sigil to the blessed spirit shield, players need 90 Prayer and 85 Smithing. Smithing the shield gives 1,800 smithing exp. Alternatively, you can ask Abbot Langley to attach it for 1,500,000 coins. It is a rare drop from the Corporeal Beast.