Julian Keller, also known as Hellion, is a young mutant with powerful telekinetic abilities, which allow him to move objects with his mind and create protective fields. Initially portrayed as arrogant and rebellious, Julian's character undergoes significant development throughout the X-Men series. He often struggles with control over his powers and the consequences of his actions. Hellion's journey includes themes of leadership, responsibility, and the complexities of growing up with immense power. He has been a prominent member of the New Mutants and the Hellions squad at the Xavier Institute. Despite his rough exterior, Julian has a deep sense of loyalty and commitment to his friends and teammates.