Kythylian Mu is an alien who is a long-time friend of Coran.
Kythylian and Coran once devised a ruse to send the Paladins of Voltron on a training mission: leading them to believe that because Coran slept for ten thousand years without making good on a bet, Kythylian would hold Coran captive. Only returning him if the Paladins brought him a Yalexian Pearl to pay off the debt. Once the Pearl was delivered, the deception was revealed. Kythylian planned to sell the Pearl to help fund the war against the Galra Empire.
- Kythylian Mu's race can live for a hundred thousand years before converting into a gaseous state.