Frost fairies

Tiny fairies that brought about freezing cold. Ina Liddell murdered Lewis Carroll by slipping into his room while he slept and opened a cage of frost fairies. They froze his lungs. The world thought it was pneumonia, but The Founder and Ina Liddell knew differently.

The Frost Fairies may be the same ones created by Margaret Canby in The Frost Fairies. The child Helen Keller wrote a very similar story.