Evie’s deal with Xerses involved getting immense amount of magic, enough to even allow her to become a dragon made of ice, unfortunately it has also led to problems. With the bonding and sudden rush of magic entering her, Evie's mental stability weakened, some would even say shattered. Her emotions and moodswings, which she seemed to already have, began to affect the magic at her disposal; allowing cold winds to blow fiercely, snow to fall, ice forming and covering the area around without her bidding, strong enough to match that of what she felt. All of which would lead to her seclusion, Seclusion which over time caused her to lose control of her magic bit by bit and leaving a permanent chill around her, after all when theres no one around worry about why should you bother maintaining it?