There are two scrolls:
-Sunflower scroll: If you somehow trying to get the other scroll without enough clue or by cheating, you get this one... It will drain all your charisma in exchange of your exp.
-(I forgot it name) scroll: This baby give you a new skill to dominate the battlefield, provided if you know how to time it... This is the scroll that you were looking for, if you have five clues, a rock to throw and then do a left-and-a-right or the other way around. I haven't tried with a conquered Derchios castle yet... Perhaps that's the problem?