Challenge Sigils are rewards debuting in Kingdom Hearts 358/2 Days. Earned after clearing Challenge Missions, the amount of Sigils you can gain ranges from one to three—the amount earned varying based on how well you stick to the Challenge's requirements. For example, if the player is requested not to miss with attacks, a certain number of missed attacks would cause the Sigil amount to drop from the the maximum, three, down to two, and eventually down to one or zero.
They appear on the screen as Nobody insignias, and can be used at the Moogle Shop to unlock new items. The player will not use up Challenge Sigils when redeeming freebies from the Moogle Shop. The total number of Challenge Sigils earned is 255.