Klarion Bleak AKA Klarion the Witch Boy is a powerful villain from the DC Universe.
Klarion is a young child, wearing all black Puritan-like clothes. He has black hair in shape of devil horns, but the most notable thing about Klarion is that he is almost never seen without his beloved familiar, Teekl the cat.
If there is one word to sum up Klarion's personality, it would be spoiled. Klarion is a selfish and mischievous brat who is willing to go through extreme lengths to get what he wants. He also finds the destruction and chaos he causes to be very amusing, thinking nothing of how it effects others. However, Klarion is still a young boy, and does throw childish temper tantrums if things do not go his way.
The New Batman Animated Series
When Jason Blood, a friend of Bruce, bid at the auction to keep the iron out of Klarion's hands, though after it seemed that the young witch-boy could out bid him, Bruce stepped in and won the auction, later giving it to Jason. Furious, Klarion was still intent on getting the branding iron, so Klarion sent Teekl to steal it.
After Teekl successfully stole the branding iron from Jason Blood, Klarion used it and casted a spell to split the demon known as Etrigan and Jason into two beings. After he split Etrigan from Jason he uses Etrigan to cause anarchy and destruction. Batman managed to steal the branding iron away from Klarion and cast a spell to rejoin both Etrigan and Jason together. Ticked off, Klarion was about to kill Batman but Etrigan intercepted the attack, defeated Klarion and banished Klarion in a crystal ball.
Jason mentioned that Klarion turned his own parents into mice, and it is heavily implied he fed them to Teekl.
Klarion along with his pet cat Teekl are one of the enemies that the superhero team known as Young Justice encounters. He's also a member of the organization known as The Light, under the alias of L-7, and is also called a Lord of Chaos, his opposite being Nabu, otherwise known as Doctor Fate.
In his first appearance in the series, he wanted the Helmet of Nabu, presumably to tip the balance between order and chaos into his favor. In another episode, he, along with four villainous magicians, Wotan, Wizard, Blackbriar Thorn, and Felix Faust, split the world into two different realities, one populated only by children under the age of eighteen, and the other populated by adults, the youngest being eighteen. He was thwarted and the two realities merged back into one.
He is briefly mentioned by Bruce Wayne in the episode "Revenant".
Powers & Skills
Klarion is an extremely powerful wizard, skilled in nearly all forms of magic and sorcery, such as necromancy, possession, and so forth. It is hinted that he might be immortal. When it comes to fighting, he can cast spells on his foes to transform and neutralize them, or blasting them with energy balls and giant spheres of destruction. However, he remains a small child, who can be physically overpowered with little trouble. His only weakness is his cat, Teekl. There's a link between Teekl and Klarion, and the further Teekl is, the weaker Klarion gets.
In Young Justice, Klarion's nature as a Lord of Chaos makes him considerably more powerful than his original counterpart. He has reality warping abilities, he can travel through wormholes and can easily dispel binding magic cast on himself. He attacks with fire balls of variable size, dragon shaped fire blasts, energy blasts and barrages of beams, among others.