The Feyy are a novel alien species that visits Euphorion every 3000 years.
The crystal stone around their neck is unbelievably powerful. If broken it can collapse worlds.
Every Feyy is given a crystal at birth and has the facility to merge with different living beings therefore finding a Feyy out of camouflage is extremely rare.
They are symbiotic with their hosts and might imbue them with wild abilities.