The Shades are the lords of the Umbral, creatures that have embraced the perpetual darkness and come to thrive in it. Within the shadowed confines of the Umbral the Shades have achieved tremendous power that leaks out into the material plane through their lesser servants and the creature’s they’ve inspired.
Outside of the Umbral they are weakened, no longer fed by the dark energies they bathe in. The Faerie is anathema to the Shades and its energies will slowly kill them should they ever enter.