A flashback in Curse of Ratilla depicts Jaga as a young cat using the Sword of Omens to defeat Ratilla. Afterwards, he placed a curse on the Sword of Plun-Darr and formed Mount Plun-Darr around it in hopes of preventing it from falling into the wrong hands.
A flashback in Between Brothers depicts Jaga as being Head Cleric when Cheetara was a child. After she failed the initiation test, Jaga cast her out because she seemingly had no patience. Cheetara swore she wouldn't leave the front door of the temple until she was given another chance. After many days of sitting in front of the doors and feeding off the petals of a Day Astrid flower, she collapsed from lack of nourishment, convincing Jaga that she did indeed have patience, finally taking her in to start her training.
In the present day, Jaga was watching Lion-O's attempt to utilise the Sword of Omens, and witnessed his sudden vision. Although Lion-O denied it, Jaga knew the boy had seen something.
When the Lizards attacked Thundera, Jaga and his Clerics fought against their technology and the traitorous Grune. The Clerics were winning the fight against them until Mumm-Ra appeared and defeated them, capturing Jaga and Cheetara in the process. Mumm-Ra attempted to force Jaga to release the spell on the Sword of Omens that prevented him from touching it. Jaga refused and was tortured for it. He and Cheetara were then saved by Lion-O and Tygra. As the group attempted to escape, Jaga had them stop so he could anoint Lion-O as the new Lord of the ThunderCats and activated his Claw Shield. Jaga then stayed behind to buy the younger ThunderCats time to escape.
Once again captured, Jaga's spirit was imprisoned within a magic lantern, which forced him to show Mumm-Ra the way to the Tower of Omens. When Mumm-Ra arrived, it was at the same time as Lion-O's group. Mumm-Ra transformed into his more powerful form, and proved too powerful for the ThunderCats. Jaga then sacrificed himself by breaking out of the lantern, creating a blinding flash that forced Mumm-Ra to retreat.
When Lion-O accessed the Book of Omens, he found Jaga's spirit within, which directed him to the knowledge he sought.
Following Lion-O's death by drowning, he was met by Jaga's spirit, who informed him that the Spirit Stone had deemed him worthy of a second chance. Jaga's spirit told Lion-O of the trials he would have to go through, opening the door to the first trial. When Lion-O failed his last trial, he offered to sacrifice his very soul for a chance to help the other. Jaga agreed, giving him until sunrise. When the time came, Jaga's spirit appeared to the assembled ThunderCats, declaring that Lion-O's willingness to sacrifice himself had indeed earned him a second chance at life.
Despite his responsibilities, he is a very relaxed individual. He has always been kind to Lion-O and speaks highly of him to his father. Jaga always encourages Lion-O to do things the way he thinks they should be done, and not worry about what his father and brother will think.
His appearance is based on the jaguar. He appears to be of a very old age, having a very thin body and sporting a long beard.
Known as "Jaga the Wise", Jaga is an elder warrior and head of Thundera's clerics, also known as the Guardians of the Crown. Adviser and protector of the royal family, Jaga has super speed, wields a magical staff, and is a formidable fighter in combat.
Interestingly, in the episode "Curse of Ratilla" a flashback clearly shows Jaga using the Sword of Omens.
- Unlike his original series counterpart, the new Jaga possess super-speed like Cheetara.
- Him fighting Ratilla with the Sword of Omens may be a nod to the old series since their eighties counterparts have battled before, using the Sword of Omens and the Sword of Plundarr.
- In the original series Jaga and Mumm-Ra was voiced by the same actor.