A mysterious scroll is given as a reward on the 7th day of the daily rewards (you need to play at least one adventure every day for 7 days to receive it).
From a mysterious/mystery scroll you can get either a title (a humorous description that shows up under your character name in-game), or a marshmallow voucher (collect these to get the marshmallow pet).
You can also find mysterious scrolls on the Royal Emporium (the virtual marketplace) if you don’t have the patience to grind the dailies.
What is the Scroll of Designation?
A scroll of designation is obtained from the mysterious scroll. The scroll of designation is the actual item that will give you a random title in-game, the title we’ve been mentioning above.