Rune Scrolls are items that can be used by anyone in your party. They are much like Runes but they only work once. They can be equipped in a free slot in a character's inventory. When used, they replicate the attack they are named after.
A scroll can be made for any rune that can be used in battle. This means runes such as the Poison Rune or the Firefly Rune cannot be made into scrolls. The only exception to this is the Bright Shield Rune and the Black Sword Rune.
You can obtain scrolls by recruiting Raura in Tinto. She will appear with all the other shops at your castle