In the original series, Jaga appears only as a spirit after passing away due to old age during the trip to Third Earth. Even still, Jaga is a key figure for the ThunderCats, most of all Lion-O ...

It featured Lion-O leading his tribe on Third Earth ... He wants to rescue Thundera from the old days—an arc that the ThunderCats movie may well copy as it's developed. Admittedly, he's innocent ...