The new home of the Thundercats, former Nobles of Thundera. Third Earth is also home to many other people and races, including Mumm-Ra, an evil sorcerous mummy bent on eradicating the Thundercats, S-s-slithe and his evil band of mutants, who sometimes work with Mumm-Ra, and even a few friendly types like the Berbils, a race of cybernetic teddy bears who help the Thundercats early on by building the Cat's Lair for them.