Waif

The Waif is a recurring character in A Song of Ice and Fire novels and It's TV series adaptation, Game of Thrones. Although not villainous at all in the novels, she serves as antagonist to Arya Stark' storyline in Braavos during Seasons 5 and 6.

Trivia

 * While in the TV series, the Waif and Arya has a somehow antagonistic relationship, in the novels, they have a generally friendly interaction with each other.
 * Her personality was drastically changed in the TV series, taking personal pleasure in tormenting Arya and is shown to be pleased when she is allowed to kill her, even more when she nearly stabs her to death.