Kastria

Kastria was the homeworld of the Kastrian species.

When the Kastrian fleet was utterly destroyed, Kastria was desolated as the Mad Mind of Bophemeral turned their computers against them in the Millennium War. (PROSE: The Quantum Archangel)

Kastria was constantly ravaged by solar winds. Eldrad created spatial barriers to allow Kastrians to live on the surface. He also developed silicon-based bodies for the species' physical needs. Eldrad also provided the Kastrians with inexhaustible power by tapping into the core of the planet as a source. Having done all this, Eldrad regarded himself as the "creator of Kastria".

Eldrad wanted to the Kastrians to conquer other worlds, but he king, Rokon denied him this. In retaliation, Eldrad destroyed the barriers. He was executed for his treason, but the planet was ravaged by solar winds, leaving it barren and cold. Forced to live a subterranean life, the Kastrians, in the words of Rokon, "chose final oblivion". They destroyed the race banks too, to prevent Eldrad from raising an army if he returned.

When he did so, he was dismayed to find himself without subjects and so decided to have the Fourth Doctor return him to Earth where he could rule over the humans. Pursuing the Time Lord and Sarah Jane Smith, he was tripped by the pair using the Doctor's scarf and fell into an abyss. (TV: The Hand of Fear)