Castle Doom is a castle, located in a large city on Planet Doom.
Voltron: Defender of the Universe Continuity
Castle Doom serves as the official residence of the Doom royal family and the headquarters of the Doom military.
The castle's centerpiece is the main keep, a large and tall building that dwarfs the skyscrapers of the surrounding city. It is shaped like a box with four horns on the top corners. The main keep contains the throne room, royal apartments, offices for military and civilian staff, and at least one detention cell block.
The throne room is where the king sits and conducts official business whenever he is inside the castle. Zarkon frequently met with Haggar and Lotor to plot the destruction of Voltron and the conquest of Arus.
The throne itself once had a hidden elevator that could take the throne to the roof of the main keep.
Tower Detention Block
A block of holding cells is located in one of the corner towers. Keith and company were held in one of these cells for at least one night.
The arena is located next to the main keep, with seating for tens of thousands. One of the sports played in the arena is gladiator combat involving robeasts and slaves. One of the box seats is reserved for the king and his guests.
Lotor once challenged Zarkon in the arena. He had lost, but Haggar convinced the king to spare his son's life.
A courtyard surrounds the main keep and is presumably surrounded by the outer wall. It is large enough for spacecraft to land.