Angela calls them "The Twisting Fae of Svartalfheim."

They are fairy folk who grow from spores in dark caves, with no access to light, where they learned to take whatever shape they want. According to Angela, there are many legends surrounding how they are woken up, but the one that she always knew revolved around a "broken bridge." She believes the destruction of The Black Bifrost may have scattered their spores to Midgard.