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Lion-O is the lead protagonist of the ThunderCats (2011 TV series). He is the son of king Claudus and brother of Tygra. As current Lord of the ThunderCats, Lion-O is a fearless leader who's ready to jump into the fight, even when it gets him in trouble. He wields the mighty Sword of Omens, the most powerful weapon on Third Earth


Young Lion-O and Tygra

Lion-O was born to King Claudus and an unnamed mother. His mother died shortly after childbirth. He never met her. He was chosen by the Sword of Omens at an early age, and he was raised alone by his father Claudus and adoptive brother Tygra. From a young age, Lion-O would always have hope and technology beliefs, much to his father's dismay. Claudus would disapprove of his son's behavior and personality, constantly trying to change him to be more like his favored older brother. Sometimes, Claudus would openly show his favoritism towards Tygra over Lion-O, but nevertheless, he loved Lion-O and hoped he would be ready to become King one day. His relationship with Tygra was unsteady during their childhood, due to Tygra's competitive streak and favoritism by the people of Thundera, especially after an experience that occurred within the Forbidden ruins, in which Tygra would push Lion-O into a pit. However, Tygra instantly regretted it and went to find help. Over the years, he grew to love Tygra, and both siblings would look out for one another. They were both even trained at an early age by Thunderian Generals Grune and Panthro.

As Lion-O grew older, he would often visit the slums of Thundera in secret to obtain old artifacts of so-called technology. He was often disgusted by the mistreatment of other animals living in the slums. When some thugs were bullying a humanoid Dog and overheard Lion-O's comments, they told him to pay up. He refused and instead fought them until Cheetara arrived and ended the fight. She wondered why a Prince was in the slums, and when the thugs found out he was the Prince, they scattered. Lion-O and Cheetara then traveled to a nearby shop that held technology, which Lion-O was interested in. He expressed his hopes and dreams of technology to become one with the people. Cheetara called him "different" because of his actions. He noticed that he was late for his ceremony of the rightful passage and left, but not before thanking Cheetara and hoping to return the favor of her saving him earlier one day. At the Palace, he arrives and greets his brother Tygra, Claudus, and Jaga. He apologized for being late, and the Clerics brought in the Sword of Omens, which would test if Lion-O would become a great king or not. He then undergoes the Ceremony of the Right of Passage. During the test, he has a vision of the future but does not understand its meaning.

Later, King Claudus welcomes the return of his friend Grune, who was sent out to find the Book of Omens alongside Panthro, who was believed to be dead and holds a celebration in his honor. During the event, Lion-O would ask Grune if he has seen any technology along the way, but Grune would deny it, much to Lion-O's dismay. After a brief competition with Tygra, Lion-O encounters a pair of captured Lizards, questioning them at why the Lizards attack his people, in which he realizes the years of persecution that his people have enforced upon the Lizards survival. He, along with Tygra and Cheetara, would defend these Lizards against a crowd of angry Thunderians and convinces his father to release them.

Soon after, Thundera is attacked by Lizards, and Lion-O is ordered by his father to stay behind while he and Tygra go into battle. However, it is then discovered that the Lizards are equipped with a vast amount of weapons and technology, much to Lion-O's horror. It is soon discovered that Grune has joined the Lizards and that Panthro is being held, hostage. Lion-O comes to his father's aid and uses the technological artifacts he bought from the slums (revealed to be bombed) against the Lizard army, allowing Claudus to rescue Panthro. Nevertheless, Panthro murders the king, then revealing himself to be Mumm-Ra in disguise, who is now the ruler of The Lizard race and manages to destroy Thundera. Lion-O is captured along with Tygra, Jaga, and an unknown cleric. Upon this, Lion-O realizes that the vision he had earlier was Mumm-Ra's destruction of Thundera, in which Tygra would express his consent on why Lion-O should not be king. However, due to his kindness to the Lizards, Lion-O was given a key hidden in his meal, allowing him to escape with Tygra. Lion-O and Tygra than rescue Jaga and Cheetara (revealed to be the unknown Cleric), with Lion-O grabbing the sword to blast Mumm-Ra out into the open as the rising sun's rays harm him. Lion-O, Tygra, and Cheetara undergo a quest to find the Book of Omens, leaving an injured and supposedly dying Jaga behind. On their journey, they pick up two young kittens, WilyKit and WilyKat, manages to save a crew of Fishmen by helping them retrieve their home from a monster called the Ramlak and aid a group of Petalars find their way home from Briar Woods.

Along this journey, Cheetara would also act as a guide and counselor to Lion-O, helping him understand and learn Sight Beyond Sight. Over time he began to develop feelings for her, but unbeknownst to him, she held deep feelings for Tygra. Eventually, Lion-O and the others found the Book in the Tower of Omens, with the help of the real Panthro, whom he and the rest managed to find along the way. However, when finding the book, Jaga is discovered to be seemingly alive as his soul was trapped within a lamp by none other than Mumm-Ra himself. Mumm-Ra than transforms into his true form and defeats all of them with ease. But before he could kill Lion-O, Jaga sacrifices himself to save Lion-O by transforming into a powerful beam of light, causing Mumm-Ra the ever living to flee. After obtaining the book, Lion-O enters it, with Jaga's spirit as his guide, and relives the moments of his ancestor Leo (the first Lord of the Thundercats), who overthrew Mumm-Ra in the past and freed other animals from his tyranny. He also discovered that there are over four Power Stones, one of them being the Eye of Thundera. By this turn of events, he understood that finding the power stones is not enough and that he must unite all the animals in order to defeat Mumm-Ra. On this quest for the power stones, he would learn to advance his swordsmanship by a warrior called the Drifter, rescue a group of robot-like bears called Berbils and master sight beyond sight by a local group of Elephants while entering the Forest of Magi Oar.


On this journey, Lion-O discovers that one of the War Stones, called the Spirit Stone, is located within a portal within a hut in the Elephant village Astral Plane. They manage to defeat Grune and the Lizards, who were occupying the Village. When Lion-O opens the Hut gateway, Cheetara kisses him on the cheek for good luck (but it was only for support). This unknowingly triggered Tygra's jealousy, which caused him to volunteer to go in with Lion-O. Before Lion-O would enter with Tygra, the Elephant leader Anet predicted that Tygra would betray Lion-O, sparking the ThunderCat's curiosity.

In the Astral Plane, Mumm-Ra would divulge Tygra and Lion-O's worst memory into reality (when he and Tygra went to the forbidden ruins), in order for both of them to destroy one another. This would cause Tygra to repeat the same event that occurred to them as children and cause him to knock Lion-O into the same Pit. Nevertheless, Tygra realizes he can never betray Lion-O, and instead saves him as they both resolve their differences. After defeating Mumm-Ra and finding the Spirit stone, the Astral Plane began to collapse, but both brothers escape in time while Grune gets sucked in, and Panthro loses his arms in the process. That night while celebrating their victory in the Elephants village, Lion-O confronts Anet tells him that his prediction was wrong, but Anet tells him that he has yet to wait until the evening bell rings. Just then, Lion-O witnesses Cheetara and Tygra kissing and is devastated, just as the Evening bell rings. This was the betrayal that Anet had predicted.

This revelation continued to eat at Lion-O's emotions afterwards, to the point where it even put him on rocky terms with Cheetara. This made things all the more difficult when Mumm-Ra's new generals: Kaynar and Addicus, joined Slithe and the Lizard Army in their battle against the Thundercats. Lion-O's clouded judgement soon led the Thundercats into an ambush set by Mumm-Ra's forces and had him fall off a cliff to his "death".

Fortunately, the Spirit Stone deemed Lion-O worthy of a second chance at life and put him through a series of trials specifically designed to test his abilities as a leader. He managed to pass three of them, but when he came to the final one (which pitted him against a spirit version of Tygra) he failed. He pleaded with Jaga's spirit to let him return and even offered his soul as payment. Jaga then told Lion-O that he had until sunrise to help his friends, because at that point, his soul would enter limbo for all time. Regardless of the consequence though, Lion-O agreed to this deal and returned to the land of the living. He followed WilyKit's markers and soon arrived at Mumm-Ra's Pyramid. There, he tricked Slithe, Kaynar and Addicus, freed the other ThunderCats and led them into battle against Mumm-Ra. Thanks to the Spirit Stone, Lion-O was able to retrieve the Sword of Omens and weaken Mumm-Ra with it. The group managed to escape the Pyramid afterwards. When sunrise finally came, Lion-O expected his demise. But then Jaga told him that because he chose to make the ultimate sacrifice to safe his friends, he proved what it meant to be a king and earned a second life.

Some time later, Tygra and Lion-O found the lost Tiger clan, and Tygra reunited with Javan, his biological father. After fighting with Shadow Creatures, Lion-O realizes that none of the tigers had left the cave, nor had they fought back. He uses the Sword of Omens' power to see that the shadow creatures were posing as Tiger cats. Javan tells him about Tygra's origin. Tygra resented Javan because he did not understand the reason behind it. Javan, looking to save Tygra from a similar fate, explains this to Lion-O.

As Tygra and Lion-O were about to leave, a group of tigers led by Caspin attempted to kill Tygra, only for him to be saved by Javan again. The tigers then turned into unconscious night creatures because of the curse, and attacked the brothers. Javan attacked Tygra, almost killing him by choking him, but by knowing the reasons why Javan gave him away, Tygra was able to forgive his father. That act of humility broke the curse. Tygra thought he would be able to stay with his father and his people, but they explain the curse kept them alive with no need of food or water, and that they are not dead, netiher alive, and one by one started vanishing, the last of them being Javan, not before telling Tygra "Always remember son, you are a tiger. I will be watching you ...with pride". After that, Tygra picked up Javan's three-sphered bolowhip and asked Lion-O if it was his destiny to always lose what he cares for; Lion-O assures Tygra "You're not gonna lose me brother".

After meeting up with the rest of the ThunderCats, they journey to the City of Dogs and discover a Cat refugee named Pumyra, who is being forced to fight as a Gladiatrix in an arena called The Pit. While WilyKit and WilyKat explore the town and find food, Lion-O orders Snarf to keep an eye on them. The group watches the "games" and witness the Cat, Pumyra, defeat a robot named Gormax with impressive skill and victory. Lion-O then asks who is in charge of the arena and is lead to Dobo, the head of the arena. He would not give up Pumyra because she was too valuable to loose. It is also discovered that Panthro was an old friend of Dobo who both fought in the arena as slaves in the past. Dobo says she must win one hundred battles to gain freedom. Lion-O isn't satisfied with Dobo's answer and decides to sneak into the cells and break Pumyra out, but as he tries to release her she begins to yell at him with anger and rage. This wakes the guards and Dobo appears, taking the Sword of Omens and the Gauntlet, telling Lion-O that since he disobeyed his law he would have to fight to earn his freedom. He is told that his first match would be against Pumyra. As Dobo returns the Sword and Gauntlet to Panthro and the others, he tells them that if Lion-O wins this fight he will go free. Panthro, Cheetara and Tygra cannot intervene in order to avoid causing a problem with the Dogs, but instead try to convince Dobo to release them. Dobo refuses and recalls how in the past Panthro had escaped one night and left Dobo alone with all the enemies they made during their slavery.

In the cell, Lion-O confronts Pumyra regarding her actions, and Pumyra reveals her anger and sadness towards him because she believed he abandoned his people when the kingdom fell and was the reason why they were sold into slavery. Lion-O claims that he did what he had to do in order to find a way to save them. Pumyra scoffs at this and states that she stopped believing he would rescue her and that she will earn the freedom that he could not give her by killing him when they enter the arena.

As the battle between Lion-O and Pumyra commenced, Lion-O refused to fight her to show his loyalty towards his people. Pumyra remained unconvinced and proceeded to beat him without any mercy. The group pleads for Dobo to stop the fight, but he refuses. Dobo says that this battle shows how loyal Cats truly are until Panthro explains why he left that night. Panthro tells him that the next battle was to be a death match against Dobo and himself. Dobo asks if he ran because he was afraid he would have lost but Panthro says that he was afraid that might have won. Lion-O continues to stand up after taking a beating from Pumyra's attacks, stating that he promised to stand by her. Pumyra learns he is truly a strong and caring king and refused to continue the fight. Dobo states that since both forfeit the match they must be sentenced to death, until he hears his people telling him to let them live.

After learning why Panthro left and witnessing the loyalty between Pumyra and Lion-O, Dobo lets them live and grants them both their freedom. With old wounds fully healed and new friends made, Lion-O asks Pumyra where the other Cats that were taken by the lizards are now and she replies "Mount Plun-Darr" as she points to an ominous looking castle.

When Pumyra joins Lion-O, Tygra, Cheetara, and Panthro into raiding Mount Plun-Darr, they discover Ratar-O and his Rats are forcing the Cat slaves to excavate the Sword of Plun-Darr. During the raid, she recalls on how she was once a slave to them before being handed over to the Dogs. When Pumyra notices Lion-O's concern for Cheetara when she and Tygra plan to infiltrate the slave ranks, she asked Lion-O if he still liked her, which he quickly denies and claims that he's over it. She then teases him that if that were the case, then "Maybe it's time you move on to someone else", to which Lion-O gives a rather flustered look.

He, Panthro, and Pumyra then go to rescue the Cat slaves, but when Pumyra sees Mordax whipping one of them, she angrily charges off and knocks him down. She proceeded to beat him until Lion-O intervened, but when he did, she simply knocked him aside and then attempted to kill Mordax, stating that she would make sure he'd never touch another cat. Lion-O once again stopped her and explained the virtue of mercy to her. She reluctantly agrees, but when Mordax captures them and brings them to Ratar-O, she blames Lion-O's mercy for getting them into said situation. However, before Ratar-O could have the three executed, the mine began to cave in (courtesy of Tygra and Cheetara finding of the Sword of Plun-Darr) and buried everyone alive. Lion-O managed to defeat Ratar-O (thanks to showing Mordax mercy) and then helped Pumyra out from under the rubble. She then says "Perhaps there is room for Mercy in our struggle" with a smile.

She and Lion-O then choose to enter Mount Plun-Darr in order to keep the Sword of Plun-Darr from Mumm-Ra's forces, as well as to buying the newly liberated cat slaves enough time to get to safety. Mumm-Ra, able to sense the sword's whereabouts, sends in Kaynar and Addicus, as well as several lizards to procure the blade, but Lion-O and Pumyra managed to avoid capture. Deciding that it is best to split up to confuse the enemy, Lion-O and Pumyra part ways, but almost immediately, Pumyra is captured by Mumm-Ra and is tied to one of the large crystals that hang from the walls of the mountain.

After a struggle for possession of the blade, Lion-O manages to get it away from Mumm-Ra, but before he can reclaim it, Mumm-Ra threatens Pumyra in an attempt to play the Lord of the ThunderCats' emotions. After then taunting Lion-O with "Will you be the first of species to choose power over emotions", he sends Pumyra plummeting to the floor, thus forcing Lion-O's hand. He abandons the sword and saves Pumyra, giving Mumm-Ra just enough time to take the swords and make his escape. The two cats, both fatigued and battered from their ordeal, then sit and talk on the floor. Pumyra apologizes to Lion-O for her treatment of her king and Lion-O pardons it, saying that she "deserves more". He then asks her to call him by name from that point on. She responds by agreeing to do so and caressing his face. The two later emerge from the mountain and report to their fellow cats about the events that had unfolded.

Cancelled Second Season

As revealed at conventions and by art director Dan Norton on a podcast interview, most of Lion-O's story for a potential season 2 was already decided on.

Lion-O and Tygra would have a clash of their ideologies when Tygra kills Pumyra to save his brother as Lion-O still believed she could be redeemed.

Lion-O then would decide he needs to go back into the Book of Omens for more training and is gone for 10 years. Lion-O would emerge from the Book of Omens 10 years later and Wilykit would eventually become romantically attached to Lion-O. Lion-O would also get a nephew when Tygra and Cheetara have a son named Bengali.

The reunited ThunderCats and the united Third Earth rebellion would engage in the final battle with Mumm-Ra, but Tygra dies saving his brother from being felled by Mumm-Ra with the sword of Plun-darr. According to Dan Norton, they were not sure if they were going to have Tygra stay dead or be resurrected.

After the defeat of Mumm-Ra and the restoration of peace on Third Earth, Lion-O assumes the throne of Thundera with a grown-up WilyKit as his queen.

If they went with the Tygra stays dead route, there would have been a scene where Lion-O shows Bengali statues of previous kings and there would be a statue dedicated to Tygra.

Physical Description

Lion-O is a Cat of average build with cream and gold-colored fur, spiky red hair, blue/teal eyes, pointed ears, small, elongated fangs, and a striped face. His attire consists of pale blue armor on his shoulders, torso, and hips, with dark blue pants that need to be held up by a large belt, and silver shin guards that also cover and protect his knees. Like all ThunderCats, he has no shoes.


Although cunning and skilled in combat, Lion-O can also be a bit of a hothead. He is the only one at the beginning to believe that technology and Mumm-Ra exists. Lion-O will immediately step up to defend anyone in need, regardless of their species, proclaiming, "No one deserves to be treated like that". His compassion won the help of one of the Lizards while he and Tygra were being held prisoner. This trait was also what caused Cheetara to think of him as different since no one else would do what he did. Sometimes Lion-O's big heart gets the best of him.

In the beginning, Lion-O tended to be a sort of ladies man, first when trying to sound mature when meeting Cheetara the first time, then later pretending to be checking out some local female Thundarians during his training with the Sword of Omens, much to his father's chagrin.

In Song of the Petalars, Lion-O was very annoyed when Snarf jumped on his face when he was having a chat with Cheetara "Are you kidding me!? Now!? This had BETTER be important, Snarf!". Despite this, he can also be quite nervous when Cheetara does the advancing, as seen in Journey to the Tower of Omens.

Lion-O, at the start of the series, showed some resentment towards Tygra for his father's favoritism towards him, wanting a chance to prove himself just as worthy of being succeeding his father as everyone else believed Tygra to be. His beliefs, however, put him at odds with his father, who had a very different ideology concerning how to lead the ThunderCats.



Tygra and Lion-O were siblings from a very early age. As Tygra was adopted into the family before Lion-O was born, he and Lion-O are seen to have an on and off rivalry. Sometimes Lion-O would show resentment towards his older brother, due to Tygra's jealousy over the crown and favoritism by Claudus, as he was able to out do Lion-O in many things. During one time as kittens, both he and Tygra were visiting the forbidden ruins, where Tygra would purposely push Lion-O into a pit, but instantly regretted it and went to find help, showing the bond they both have as siblings. When entering the Astral Plane, their relationship became more complicated and Lion-O, having heard of Anet's prediction that he would feel betrayed by Tygra, was much more cautious, but instead he and Lion-O resolved their differences. However the betrayal, unintentionally, was from not Tygra alone but Cheetara as well. Lion-O was shocked, when he saw Cheetara and Tygra kissing. Lion-O tried to hide his heartbreak, but ultimately couldn't, which led to some tension between him and the new couple. When Lion-O "died" Tygra was made king in his place, but he soon started to see just how much pressure the position carried and ultimately gained a new found respect for his younger brother. In "Native Son", it was made clear that despite their rivalry, Lion-O still views Tygra as a brother and would do anything thing to help. At the end of that episode, when Tygra asked if he was doomed to lose everyone he cared about, Lion-O comforted him by saying, "You're not gonna lose me, brother" to which Tygra gave a smile.


Cheetara first met Lion-O while he was visiting the slums. They developed a close friendship together and overtime she became guide and counselor to him. She called him different, stating that there was a reason on why the Sword of Omens chose him, and shared his compassion for other animals. Lion-O then began to develop feelings for her but unbeknownst to him she held deep feelings for Tygra. One time, Cheetara actually kissed Lion-O on the cheek, (though it was only for support). Lion-O was shocked, when he saw Cheetara and Tygra kissing. While trying to feel happy for them, Lion-O couldn't shake the angry feeling of being mislead by Cheetara from all their seemingly tender moments. However, after the Spirit Trials, Lion-O claims to have come to over his feelings regarding Tygra and Cheetara's romance. If nothing else, he appears to have gotten over his anger with Cheetara.


Claudus was Lion-O's stern and loving father. He did not approve of Lion-O's beliefs in technology and would question Lion-O's judgement and duties as prince, always hoping he would be more like Tygra. Sometimes Claudus would openly show his favor of Tygra over Lion-O, but in the end he loved Lion-O very dearly. At the time of Thundera's downfall and Claudus's death, his last words to Lion-O and Tygra were "No matter what happens, you've made me proud today".


Pumyra initially held a grudge against Lion-O, claiming that he abandoned his people. But upon seeing how much he truly cared for his fellow Cats, she was quick to forgive him. Though her resentment towards him about being enslaved remained until Birth of the Blades, when he saved her from Mumm-Ra and allowed him to escape with the Sword of Plun-Darr in the process. She deemed herself unworthy of Lion-O's compassion after that, since he saved her despite the way she treated him. But Lion-O insisted that after all Pumyra has been through, she deserves more and to call him by name instead of his title, she responds by caressing his face. Over time he developed feelings for her and would often have trouble showing them. He appears to be far more taken with her than he was with Cheetara and makes attempts to openly court her, many of them ending in disaster and serve only to confuse or annoy her. After being told to just be himself and saving her life again from Mumm-Ra, she rewards him with an enthusiastic kiss on the cheek. However Pumyra's true nature was revealed during the events of What Lies Above

Lion-O soon learned that Pumyra was loyal to Mumm-Ra all along as she was an operative revived by Mumm-Ra to seduce Lion-O and turn on him. Seeing her assist Mumm-Ra retrieve the Third Powerston deeply hurt Lion-O's feelings for her along with learning that she still blamed Lion-O for abandoning her.

Wilykit and Wilykat

At first Lion-O and the other Thundercats thought of them as helpless children and assumed that allowing them to journey with them would be dangerous. Over time the pair proved themselves as valued allies with their pick pocketing skills and ability to make friends. After watching Pumyra's betrayal Wilykit would assist Lion-O as the new cleric and adviser.


Lion-O knew of Panthro as a wise soldier however when he witnessed Mumm-Ra in Panthro's form he assumed him a traitor. However he managed to win Lion-O over after aiding the Thundercats out of danger. However Panthro at first didn't treat Lion-O as his king when they first met as he still saw him as child pretending to be a king. However after Lion-O aided him in the tunnels of Third Earth to retrieve Thunderium to power the Thundertank he recognized him as his king. However Panthro refuses to let him drive the Thundertank.


  • Tygra: (about WilyKat and WilyKit) We can't just leave them here.
  • Lion-O: We’re on a mission to avenge our father and you wanna play babysitter?! They're just gonna have to take care themselves, Tygra! Now let's go!
  • Lion-O: Oh Whiskers!

(whenever something goes wrong in a bad way.)



  • Will Friedle is a very vocal ThunderCats fan. The original show is one of the reasons he got a job in animation in the first place.
  • Friedle is best known for his role as Cory's elder brother Eric Matthews on the sitcom "Boy Meets World" and its Disney Channel sequel "Girl Meets World", as well as voicing Batman/Terry McGinnis in Batman Beyond, Ron Stoppable in Disney's Kim Possible, Blue Beetle/Jaime Reyes in Batman: The Brave and the Bold and Doyle Blackwell in The Secret Saturdays.
  • Likely one of the most noticeable differences between the two incarnations of Lion-O is their eye colors. Lion-O's were red/brown in the original series; while in this version, his eyes are teal.
  • He sometimes says "Whiskers" as a curse word when he or the others are in trouble.



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