Fear Me — 2

The thing about a spell was it never lasted forever. Every spell was but for a time. Especially a spell cast by a witch who had been killed after filling her purpose. The witch no longer lived, which meant the spell would eventually expire. The thought never crossed Benjamin's mind, who thought he had been smart, but witches were as cunning as Fae and she never told him that the spell should be renewed else it ran out of juice. 

Unlike Benjamin, Azula had been pretty much aware of that and had been biding her time. She had not just been screaming and wallowing in misery during her time in solitude. She had been thinking of ways to shatter the chains and the wrath she would pour down on all dark Faeries once she was free.