Magica De Spell

Magica De Spell is a one of Clan McDuck's most powerful villains. She was trapped inside Scrooge McDuck's Number One Dime for years causing her to create Lena Sabrewing, her niece, so she could retrieve the dime through Lena, set herself free and seek revenge on Scrooge and his family.

Fanon
She casted a spell over Duckburg causing people to go missing every now and then. It is unknown what kind of relationship she has with F.O.W.L overall.