Together with Abra Kadabra Klarion attempts to steal the Helmet of Fate. After Abra Kadabra has kidnapped Doctor Fate, Klarion watches with his cat Teekl as Abra Kadarba interrogates him about the location about the Tower of Fate. Teekl warns Klarion about intruders coming and by use of his magic, Klarion sees the arriving Young Justice team.
By following the Young Justice team, Klarion and Kadabra are able to enter the tower as well. By using a necklace impersonating Fate's voice, they manage to continue their way up the tower. However, they soon get trapped inside the staircase and Nelson, who gets his staff back by help of Artemis and Kid Flash flees with the two - leaving Klarion and Kadabra trapped on the staircases. The two however manage to escape as well and Klarion follows Fate and Kid Flash to the top of the tower where Doctor Fate is struck by Klarion with a magical blast to the heart. Before dying, Fate manages to create a magical sphere around Kid Flash. Klarion attempts to break the barrier and succeeds but Kid Flash puts on the Helmet of Fate. This allows Nabu, the Lord of Order, to take control over Kid Flash's body and to fight Klarion. When he is unable to defeat Nabu, Klarion rages which changes his appearance into something more demonic.
Nabu then claims that it is difficult for a Lord of Order or a Lord of Chaos to maintain a physical appearance. Nabu solved this problem by using whoever wears his helmet as a host but he remarks that Klarion works otherwise. He then targets Klarion's cat, blasting him away and momentarily dissolving Klarion. Afraid that the end of his cat, the vessel binding him to this world, would mean him being re-imprisoned in his own dimension for an unknown length of time, Klarion flees by teleporting away.
At the end of the episode, Klarion is revealed to be one of the leaders of the secret organization known as The Light.
At the beginning of the episode, Klarion performs a magic ritual and summons Wotan, Blackbriar Thorn, Felix Faust and Wizard to assist him. The wizards continue the ritual, chanting in German. The ritual targets people all around the world, making all adults over eighteen years disappear in the eyes of children and adolescents. This also includes members of the Justice League and even Klarion is affected - the other four sorcerers disappear. Meanwhile, in the eyes of the adults, the children are those who disappear. This causes worldwide chaos as children as well as adults to panic, believing their loved ones are gone. In truth, Klarion merely separated the two dimensions so two worlds exist simultaneously.
When both Justice League and Young Justice team realize what has happened, they decide to defeat the sorccerers. The Justice League attack the four grown up mages while the Young Justice team attacks Klarion. Klarion easily blocks all their attempts to cancel the ritual circle and casts a spell on his cat Teekl which turns Teekl into a cat-like monster. As Klarion continues to attack the youngsters, Zatanna dons the Helmet of Fate. Nabu once more fights Klarion and manages to defeat and trap the Witch Boy. When the dimensions are merged again, Klarion escapes through a portal.
After his successful escape, Klarion contacts the other members of The Light. They congratulate him on the effectiveness of his distraction as nobody has noticed that Sportsmaster and Edward Nygma used the chaos to steal a flesh sample of Starro.
In this episode, Klarion and the Brain order Sportsmaster to retreive T.O. Morrow to join their cause. As Morrow is in a coma, Sportsmaster frees Professor Ivo instead. Although Klarion is unhappy at first, he then accepts Ivo and sets him up with equipment to build new androids.
Together with Brain's tech and Ivo's androids, Klarion experiments on Starro's tentacle sample. Klarion performs magic on the tentacle. Together, they manage to power up the tentacle before Artemis storms into the room. Artemis tells the present villains to freeze and Klarion sarcastically complies, teleporting himself and his allies away while leaving ice statues of themselves behind.
After the Light has used Starro Tech to mind-control the entire Justice League, Klarion monitors them all from the Watchtower, the League's fortress in earths orbit. When Red Tornado and Black Canary are freed from the control and attempt to fool Vandal Savage, Klarion reveals that they are aware of who is under their control and who is not.
Unbeknownst to Savage and Klarion, the rest of the League has also entered the Watchtower and is targeting Justice League members, managing to counter the effects of the Starro tech on four of them. Klarion finds out before he is attacked by Black Canary. Through a portal, he calls in Martian Manhunter, Superman, Batman and other League Members to assist them. Other League members are dispached to fight the remaining Young Justice members. Klarion controls each of the League members but loses more and more of them to the anti-Starro-vaccine. After losing all their assets, Savage tells Klarion that they need to leave immediately. With Savage, Klarion flees the station through a portal.
- 1x07: Denial
- 1x14: Revelation
- 1x19: Misplaced
- 1x23: Insecurity
- 1x26: Auld Acquaintance