Crystal is a Soul Demon. Much like Fire, Earth etc. It moves through this relm and many others.
In our relm we can easily control it at will if it has chosen us. But in the otherworld... it can persuade us.
Those with this element always seem to be caught in a dreamy state. They get visions lots and can struggle controlling their thoughts. They also tend to misunderstand/confuse things sometimes. Creatures of crystal tend to be suttle and easily troubled.