Ethan used the cage as another form of torture and one he could often use to make sure she didn't step out of line. Whatever 'stepping out of line' really meant. Looking back, she knew the smallest of actions that were never intentional would end up with Ethan losing his temper and striking her, or throwing her in that cage, left alone in the dark. But the cage tormented her the most; she would be dragged down to that basement, and no matter how much she begged, it never seemed enough, and she would always end up in that cage, curled up into a ball.
It was the worst of her punishments. She'd never felt so alone in the world. Even in her 'loner' wolf days at the Hellhound's base, she was free to roam around if not for the leash of orders around her neck, and she still had Marcus there. Even with their antagonistic and strange relationship, he was the one that kept the emptiness of her gruesome crimes at bay.