The Underneath

The Underneath (TV: Brave-ish Heart) was home to the Shadow Kin. Corakinus ruled from the Shadow Palace. It had a blue star. The Shadow Realm was 9,000 years of space travel away from Earth. (TV: Co-Owner of a Lonely Heart)

Cracks in the skin of the universe opened gateways from the Shadow Realm to other planets such as Rhodia and Earth. The Shadow Kin ventured through these gateways and declared war on the planets they reached.