A mere child of thirteen years old at the time of Thundera's destruction, Lion-O aged to adulthood during the trip to Third Earth when his suspension capsule failed to prevent him from aging too much. Although cunning and skillful, he is truly a child in a man's body, and throughout the series, must learn what it takes to become a true leader and gain true maturity. In the latter half of the show's first season, Lion-O has to put all that he has learned to use in the "Anointment Trials", which consist of contests of strength, speed, cunning, and intelligence (this last is referred to as "mind-power" in the story arc) against each of the other ThunderCats. Complicating matters for Lion-O, he is required to be unarmed for the contests. The other ThunderCats are not permitted to assist him. The Mutants attempt, but ultimately without success, to take advantage of this last condition in an effort to leave the ThunderCats leaderless. Ultimately triumphing over Mumm-Ra in a final battle ("The Trial of Evil") in the heart of the villain's pyramid, he discovers that
Mumm-Ra is dependent upon his
sarcophagus, Lion-O is crowned the true Lord of the ThunderCats in a grand
inaugural ceremony attended by nearly every inhabitant of Third Earth. It is hinted that he has romantic feelings for Cheetara, Willa, and Mandora. ==2011 series==