Gusha to Yokukai no Leviathan

Tetsu Makaino is an ordinary middle school student harboring a single, earnest desire: to make genuine friends and experience a normal life. However, the purity of his simple wish unexpectedly catches the attention of Leviathan, a powerful demon from another realm. Intrigued by the boy's untainted heart, the otherworldly entity extends a tempting offer that promises to change Tetsu's reality forever. Leviathan proposes a dark bargain—in exchange for taking possession of Tetsu's physical body, the demon will grant him extraordinary, inhuman abilities. For a lonely teenager desperate for connection, this supernatural pact presents an overwhelming dilemma, blurring the lines between salvation and self-destruction as he weighs the cost of his deepest longing against his very existence. Accepting this dangerous deal sets Tetsu on an irreversible path far removed from the ordinary adolescence he once envisioned. Rather than leading to a peaceful life among peers, the agreement serves as his formal invitation into a terrifying and hidden underworld. Soon, Tetsu finds himself drawn toward a sinister gathering known as "A Feast of Demons," where the true consequences of his pact with Leviathan begin to unfold.