Jugemu is a central figure in the anime, a mysterious and powerful man who first appears as a savior to the protagonist, Rinne, during a failed exorcism. His background is largely shrouded in mystery, though he is known to be an adult male with distinctive red eyes and short, red hair that falls to his ears. He is recognized for his unique ability to permanently eliminate specific creatures that other exorcists cannot, monsters that possess black crystals allowing them to regenerate endlessly. This power sets him apart and defines his primary role as a key fighter against these significant threats.

Jugemu's personality is reserved and enigmatic, often refusing to provide direct answers to pressing questions about his identity, the nature of the monsters, or his goals. He operates with a sense of purpose and determination, focusing on his mission to destroy these powerful creatures and secure a vital artifact known as the Primordial Orb or Master Orb. Despite his guarded exterior, he forges a crucial alliance with Rinne, journeying with her across different worlds under threat and becoming an instrumental figure in her life and mission. He is frequently accompanied by a woman named Neo, who supports him in battle.

Throughout the story, Jugemu is at the center of the conflict against devastating forces, including a masked man known as an Astrophage who leads an army of core holders. His role is that of a powerful protector, yet he is not invincible. In a critical turn of events, after defeating a powerful fiery monster, Jugemu is suddenly and brutally attacked by a boyish Astrophage and torn apart, a moment that has significant repercussions for Rinne. This event highlights the immense dangers he faces and serves as a catalyst for other characters' development. His abilities are primarily focused on combat; he is shown battling monsters in intense action sequences and possesses the strength to defeat formidable creatures that others cannot.