The Merry Potters is one of the Crafting guild on Blade and Soul.
This guild is a "special" guild because many others need items crafted by The Merry Potters.
Currently it requires 1 book to unlock all craftables.
This guild also crafts two item to finish tutorial quests (Purple), Purification Jar and Serpent Calling Bell.
Premium Tempered Bowl, Premium Tempered Clay Refiner and Purification Jar require Merry Potters Secret Technique - Moonwater to be unlocked.
If you leave the guild after you unlock any of this, you will be reset to level 1 and all items locked again.