There are three scrolls hidden in each level. The first time they are collected, they reveal a piece of the story behind Mark of the Ninja, and reward you with a relevant Haiku and, when you complete the level, a point of Honor (which can be spent on upgrades). Scrolls also award you with +1000 points, regardless of whether it is the first time you've collected it. One scroll per level will be hidden in a secret Challenge Room.