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The Zaons were a green-skinned humanoid species native to Zaos. The Second Doctor had encountered them at least once before, finding them to be friendly.

On a subsequent visit to Zaos, the Doctor learned that the Daleks had invaded their world, and learned from the Zaon leader Arkadus that they intended to use the planet as a base to attack Earth. The Zaons fought the Daleks while the Doctor and the Sky Ray Space Raiders sought the assistance of the Astrobeetles, who agreed to help destroy the Daleks. Afterwards, the Space Raiders and the Zaons assisted the Doctor in repairing his damaged TARDIS. The Zaons and the Astrobeetles remained allies. (PROSE: Daleks Invade Zaos)