Wily Kit and her twin brother, Wily Kat, are the mischief makers of the Thundercats. They fly around on hoverboards and use their handy bags of tricks to confuse and bewilder their opponents. Although initially appearing the same age as Lion-O, when he aged on the trip from Thundera to Third Earth, they did not appear to (or it affected them less).

Wily Kit tends to be more cautious than her brother, Wily Kat, but will still follow him into any situation, typically putting them both in great danger. If not for the protection of the other Thundercats, they would have been captured long ago.