ThunderCats (comics) entered the Book of Omens to begin his training and claim his rightful place as Lord of the ThunderCats, but Mumm-Ra uses a powerful spell to keep Lion-O trapped in the book for several years in real time, not "Book" time, and seizes control of Thundera afterwards. In the follow-up mini-series, "The Return" (written by Gilmore and illustrated by Benes, Pimental and Lea), published in 2003, Lion-O returned to Thundera to find it enslaved to Mumm-Ra. Several of the ThunderCats are scattered. Panthro, who was left in charge while Lion-O was away, was forced into slave labor. Tygra and Cheetara
ThunderCats (1985 TV series) already on the 3rd earth. As the first few episodes progress the new writers seem to use Thundera but it isn't clear if they are referring to a planet or kingdom. Former Lion-O voice actor Larry Kenney returned to play the role Lion-O's father Claudus in the opening two-part episode of the new series. In January 2011, a promotional poster featuring re-imagined designs for Lion-O, Cheetara, Panthro, and Tygra as well as design for the Sword of Omens and vehicles were shown at the London Toy Fair. Cartoon Network aired an 80-second trailer during the After Party Special of the