Lily, sometimes referred to as Lily the White, was a wizard from Dominaria. She was the wife of Gull, and had two children with him.
Lily was born into poverty and prostitution, sold by her mother. She was supposedly hired by Towser to be in his harem. He really hired her because she showed magical prowess by wearing an amulet that noticed magic. When Gull and Greensleeves joined Towser's caravan, Gull fell in love with Lily.
When Towser's convoy finally reached a coastal city, the three left his employment. However, the power hungry wizard was scheming to steal Greensleeves' powers. He kidnapped the girls and teleported Gull to a remote tropical island. Just in time, Lily discovered her own magical ability to summon Gull back. Towser was defeated, and afterward, along with Greensleeves, began to create an army to fight evil wizards.
On Lily's magic
Initially, she told of the ability to only know one spell, but she was later able to expand on this. Lily harnessed both white and blue magic, in the prerevisionist books, "air and white magic."
She could levitate/fly/jump, create a circle of protection/sanctuary.