Manticore is a creature that appears as the primary antagonist in the first story arc of Boogiepop and Others. It is an imperfect clone of Echoes, an extraterrestrial being sent to Earth to observe and judge humanity. The clone was created by the Towa Organization, a secretive group involved in human evolution experiments, but it escaped from the laboratory where it was held. Its primary initial motivation was self-preservation and survival.

In order to hide its true nature and move freely among humans, Manticore killed and consumed Minako Yurihara, the top student at Shinyo Academy, and assumed her physical appearance. After taking her form, it was discovered by a fellow student, Masami Saotome, who witnessed the transformation. Rather than killing him, Manticore was convinced by Saotome that he could be useful, and the two formed a partnership that eventually deepened into a genuine romantic attachment. Together, they began to produce and distribute a highly addictive drug known as Type S, while also killing students to satisfy Manticore's need to feed on human flesh.

Manticore's personality is complex. It is a man-eating monster, referred to by Boogiepop as the Man-Eater, and its name itself means man-eater. It possesses a cold, predatory instinct, yet it also develops a capacity for love and loyalty toward Saotome, with whom it shares a vision of conquering the world. Its intelligence is evident in its ability to manipulate others and plan elaborate schemes. However, it is ultimately driven by its hunger and its desire to protect its own existence and its relationship with Saotome.

Throughout the story, Manticore's primary relationships are with Masami Saotome, its human collaborator and lover, and with its creator and original, Echoes, whom it seeks to destroy. It also opposes Boogiepop, the alter ego of Touka Miyashita, and Nagi Kirima, a student investigator. Its role in the narrative is that of a threat that brings together various characters and forces the intervention of both Echoes and Boogiepop.

Manticore's notable abilities include the power to consume a human being and then perfectly take on that person's appearance and mannerisms. It also possesses superhuman physical strength and resilience, as befits a clone of an alien entity. It can fight on equal terms with Echoes and is capable of overpowering ordinary humans with ease. Its defeat comes when Boogiepop traps it in a wire and an arrow is shot through its head, after which it is destroyed by the light Echoes transforms into.

The character's development is limited but significant. It begins as a frightened escapee seeking only to survive, then grows into a calculating predator who finds unexpected emotional connection with Saotome, and finally is killed while trying to protect him. Its arc highlights themes of identity, hunger, and the nature of humanity as seen through a non-human perspective.