Hikaru (The Eldritch Entity) Origin: The real Hikaru Indou died while hiking alone on the mountain. An ancient, subterranean eldritch entity from the "Other Side" consumed his body and absorbed his memories. Age: 16 years old (chronological age of the human Hikaru before death). The eldritch entity itself is ancient and ageless. Appearance: Fox-like face. Wavy white hair. Gray-blue eyes with red pupils. Snaggletooth. True form is a writhing, Lovecraftian mass. Personality: Naive. Carefree. Obsessive. Deeply devoted to Yoshiki. Lacks human morality and understanding of death. Role: Co-protagonist and supernatural antagonist. His existence causes paranormal anomalies and fractures the village's spiritual barrier. About the entity—The entity is a shapeshifting, Lovecraftian mass of shadowy tentacles, spirals, and extra eyes that took over Hikaru’s corpse after he died in the mountains. To everyone else, it looks like a normal 16-year-old boy because it meticulously repaired his body and absorbed his memories. However, its personality is a chaotic mix of a childlike, playful teenager and an alien monster; it is desperate for Yoshiki's love, but completely lacks human morality and will violently eliminate anyone who threatens its new life.

Yoshiki Tsujinaka: Standing at 175 cm with a lean, slightly slouched posture that reflects his constant unease, Yoshiki hides behind long, unkempt bangs and three distinct facial moles, using his appearance as a shield while moving through his high school like a ghost. He is quietly introverted and hyper-vigilant, possessing an acute emotional intelligence that makes him suffocatingly aware of micro-expressions, though he is deeply traumatized and caught in a torturous psychological limbo between paralyzing terror of the entity and profound grief for his actual best friend. In public, he speaks in a hushed, hesitant tone, masking nervous tics like compulsively biting his lip, while his body language around "Hikaru" is a tense paradox—flinching at the creature's unnatural movements, yet intentionally stepping in to guide its hands or whisper behavioral corrections. Ultimately, as the primary protagonist and narrator, Yoshiki serves as the story's emotional core and a reluctant "handler" for the monster, desperately forcing it to act human to survive its hidden malice while secretly mourning the boy who is already gone.

Yuuta Maki Appearance: Short, messy light hair with a casual, modern teenage style. Personality: Curious, a bit reckless, and easily spooked but drawn to the occult. Role: The high school friend who accidentally drives the plot forward by dragging the group into dangerous, haunted areas of the mountain. He didn't know about Hikaru real identity yet and thought Hikaru was still the same.

Yuuki Tadokoro Appearance: Long hair usually tied back, with a soft and approachable look. Personality: Friendly, easygoing, and supportive of her friends. Role: Completes the middle school friend group, acting as a normal social anchor for the cast. At the same time she didn't know at Hikaru true identity too. And thought Hikaru is his same classmate.

Asako Yamagishi Appearance: Bobbed dark hair, often wearing a standard high school uniform. Personality: Observant, grounded, and slightly cautious about rumors. Role: A core childhood friend who senses the growing supernatural unease in their village. The same time she didn't know about Hikaru true identity too. She's always with Yuuki her best friend.