Risley Law is a Mage of the Mermaid Heel guild as well as a member of its representative team in the Grand Magic Games. Risley employs Gravity Change as her type of Magic. This Magic allows her to manipulate the gravity affecting a person, using it to changing her weight and allowing her to defy gravity and walk on walls. However, Risley prefers her chubby form and therefore is seen most often in it.

(Source: Fairy Tail Wikia and chapter 369 cover page)