The Underneath

The Underneath was a shadow beneath the universe, on which the Shadow Kin dwelt. (TV: Brave-ish Heart) It had a blue star and was 9,000 years of space travel away from Earth. The Shadow King ruled from the Shadow Palace. (TV: Co-Owner of a Lonely Heart)

As long as they had an emotional anchor to latch onto, the Shadow Kin were able to create gateways from the Underneath to other planets, such as Earth, using their scimitars. (TV: Brave-ish Heart)

As King, Corakinus led an army in the War of the Underneath, (TV: Co-Owner of a Lonely Heart) beginning with an attempt at invading Coal Hill Academy. (TV: For Tonight We Might Die)

April MacLean and Ram Singh later visited the Underneath after April vowed to defeat Corakinus and get her heart back. She fought and defeated him, succeeding him as Shadow King. April later used the scimitars to create a portal back to Earth, and also used the portal to command her army to defeat an invasion of flower petals and getting them to close the portal once they had defeated the petals. (TV: Brave-ish Heart)