In the first half of stage 4 the player will eventually move to the right to face 2 green skulls, then climb a platforming section resembling a staircase before progressing to the left. With Arthur in gold armor and while using the crossbow weapon, stand at the top of this staircase and use his "Discover" magic (by pressing and holding the shot button) to reveal an otherwise inaccessible treasure chest. As the activation point for this chest is actually in the wall to the right of the chest, using this "Discover" magic is the only possible way to gain access.