# I'm a Behemoth

I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet also known simply as Beheneko is a Japanese light novel series written by Nozomi Ginyoku and illustrated by Mitsuki Yano. It began serialization on the user-generated novel publishing website Shōsetsuka ni Narō in August 2017. It was later acquired by Micro Magazine who began publishing it under their GC Novels imprint in March 2018. A manga adaptation illustrated by Taro Shinonome began serialization in Hakusensha's Young Animal Arashi magazine in March 2018 before being transferred to the Young Animal magazine in July of the same year. An anime television series adaptation produced by Zero-G and Saber Works aired from January to March 2025.

## Plot

An unnamed knight is killed and reincarnates as a baby behemoth, one of the greatest monsters, which happens to resemble an ordinary cat. A beautiful elf girl named Aria adopts him as a pet and names him Tama. He quickly falls in love with her, and when he demonstrates his incredible powers to protect her, everyone assumes that he is an elemental cat. Aria had bad experiences with men but grows to love Tama, and several other females fall in love with him too.

## Characters
### Tama (タマ)

    Voiced by: Tasuku Hatanaka, Riho Sugiyama (cat)

### Aria (アリア)

    Voiced by: Hinaki Yano

### Vulcan (ヴァルカン, Varukan)

    Voiced by: Tomori Kusunoki

### Stella (ステラ, Sutera)

    Voiced by: Hitomi Ueda

### Lily (リリ, Riri)

    Voiced by: Nonoka Ōbuchi

### Feri (フェリ)

    Voiced by: Yū Wakui

## Media
### Light novel

Written by Nozomi Ginyoku, I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet began serialization on the user-generated novel publishing website Shōsetsuka ni Narō on August 19, 2017. It was later acquired by Micro Magazine who began publishing it with illustrations by Mitsuki Yano under their GC Novels imprint on March 30, 2018. Two volumes have been released as of October 2018. During their Anime Expo 2019 panel, Yen Press announced that they licensed the light novel.
| No. | Original release date | Original ISBN | North American release date | North American ISBN |
| 1 | March 30, 2018 | 978-4-89-637700-2 | July 21, 2020 | 978-1-97-533294-5 |
| 2 | October 30, 2018 | 978-4-89-637829-0 | November 17, 2020 | 978-1-97-530840-7 |

### Manga

A manga adaptation illustrated by Taro Shinonome began serialization in Hakusensha's Young Animal Arashi magazine on March 2, 2018. The manga was later transferred to the Young Animal magazine on July 13 the same year. The manga's chapters have been collected into twelve tankōbon volumes as of December 2024. During their Anime Expo 2019 panel, Yen Press announced that they also licensed the manga adaptation.
| No. | Original release date | Original ISBN | North American release date | North American ISBN |
| 1 | October 29, 2018 | 978-4-59-216271-1 | April 21, 2020 | 978-1-97-539923-8 |
| 2 | March 29, 2019 | 978-4-59-216272-8 | July 21, 2020 | 978-1-97-539952-8 |
| 3 | October 29, 2019 | 978-4-59-216273-5 | November 9, 2021 | 978-1-97-532131-4 |
| 4 | March 27, 2020 | 978-4-59-216274-2 | March 22, 2022 | 978-1-97-532333-2 |
| 5 | November 27, 2020 | 978-4-59-216275-9 | October 25, 2022 | 978-1-97-533455-0 |
| 6 | May 28, 2021 | 978-4-59-216336-7 | April 18, 2023 | 978-1-97-534950-9 |
| 7 | February 28, 2022 | 978-4-59-216337-4 | August 22, 2023 | 978-1-97-536231-7 |
| 8 | October 28, 2022 | 978-4-59-216338-1 | January 23, 2024 | 978-1-97-537367-2 |
| 9 | April 28, 2023 | 978-4-59-216339-8 | May 21, 2024 | 978-1-97-538851-5 |
| 10 | October 27, 2023 | 978-4-59-216340-4 | October 15, 2024 | 978-1-97-539694-7 |
| 11 | March 29, 2024 | 978-4-59-216428-9 | February 18, 2025 | 979-8-85-541021-1 |
| 12 | December 26, 2024 | 978-4-59-216429-6 | — | — |

### Anime

An anime television series adaptation was announced on March 18, 2024. It is produced by Zero-G and Saber Works, and directed by Tetsuo Hirakawa, with Kanichi Katō in charge of series scripts, Tomoyuki Abe designing the characters, and Yūsuke Shirato and Oni composing the music. The series aired from January 4 to March 22, 2025, on Tokyo MX and other networks. The opening theme song is "Saijōkyū no Kokoro" (最上級の心, Supreme Heart) by Nonoka Ōbuchi, while the ending theme song is "Rimi" (リミー) by Poka Poka Ion, a special music unit of voice actresses Nao Tōyama and Kiyono Yasuno. Sentai Filmworks licensed the series under the title Beheneko: The Elf-Girl's Cat is Secretly an S-Ranked Monster! in North America for streaming on Hidive. Muse Communication licensed the series in Asia-Pacific.

#### Episodes

| No. | Title | Directed by | Written by | Storyboarded by | Original release date |
| 1 | "The Elf Girl and the Knight's Vow" Transliteration: "Erufu Musume to Kishi no Chikai" (Japanese: エルフ娘と騎士の誓い) | Takashi Asami | Tetsuo Hirakawa | Tetsuo Hirakawa | January 4, 2025 (2025-1-4) |
| A knight is killed by a demon and reincarnates in a dungeon as a baby behemoth, which looks like a cat. He kills and eats a slime, wyvern, minotaur, golem, and poison serpent and gains their abilities, and learns how to store items in a pocket dimension. A young elf girl named Aria enters the dungeon. The behemoth finds a treasure chest, but touching it teleports him to a hostile earth dragon. He escapes with heavy injuries, then Aria finds him, takes him home, and nurses him back to health. When he is healed, he discreetly follows her to the dungeon, vowing to protect her. She kills goblins, then he saves her from a goblin mage. They return to her guild where a man named Kasman sexually harasses her, prompting the behemoth to attack him. Kasman draws his sword, but the guild receptionist, Arnold Holzweilzenegger, makes him leave. Aria names the behemoth Tama and says he is her pet. They bathe and she confides that as a child, demons attacked her village until they were saved by Alisha the Sword Saint, which made her aspire to be just like Alisha. Later, Kasman got a paper from a baron to have Tama euthanized, then challenges Aria to a duel. If she wins, Tama will live, but if he wins, she must marry him. He allows her to have a partner, but only Tama volunteers. With Arnold as the judge, the duel begins and Kasman swiftly overpowers Aria, but Tama uses his powers and beats Kasman, ending with his own sword falling on his groin. Everyone mistakes Tama for an elemental cat as Aria is declared the winner and allowed to keep him. ||||||
| 2 | "The Tiger-Eared Blacksmith and a New Skill" Transliteration: "Tora-mimi Kaji-shi to Aratanaru Skiru" (Japanese: 虎耳鍛冶士と新たなるスキル) | Keita Nakano | Toshiaki Satō | Takashi Asami | January 11, 2025 (2025-1-11) |
| Tama learns Aria's ears are an erogenous zone. Aria goes to the tiger-eared blacksmith Vulcan to get armor for Tama made. Vulcan decides to go with them to the dungeon to learn why Aria's swords keep breaking. Vulcan easily kills goblins with her massive hammer and power over fire. Aria's swords break against tentacled roper monsters. Vulcan deduces that her high-speed fighting style is unsuited for swords and passes her daggers with which she kills the ropers. Tama discreetly eats one to gain its powers. While they bathe in a spring, Vulcan warns Aria that elemental cats can interbreed with other species and tend to rape others when they go into heat, but Aria gets excited and looks forward to that, freaking the others out. While fighting a minotaur, Tama saves Vulcan from falling debris, making her become attracted to him. They decide to be a team. Tama learns he has the potential to evolve to his next stage, but he refuses because he wants to stay Aria's cat. Aria and Tama save an orphan girl named Lala from bullies and take her to the church. Arnold promotes Aria from Rank D to Rank C, then tells the team that demons are attacking the nearby town of Lenard and abducting people. Aria is determined to stop them. ||||||
| 3 | "Urgent Quest - Defeat the Demons!" Transliteration: "Kinkyū Kuesuto Mazoku Tōbatsu e!" (Japanese: 緊急クエスト 魔族討伐へ！) | Keita Nakano & Kentaro Mizuno | Tetsuo Hirakawa | Shin'ichi Watanabe | January 18, 2025 (2025-1-18) |
| Aria, Vulcan, and Tama join a party led by Cedric Ruine and composed of Danny, Howard, Keni, and Mariette, all heroes who won a previous war against the demons. Cedric and Arnold are in a relationship. The party goes to Lenard and bathes in a hot spring. Danny and Howard attempt to peep on the girls, but Tama stops them. The party goes to the demons' lair. The demons' leader, Beryl Astaroth, sends werewolves at them that are defeated. He reveals himself and explains he seeks revenge on humanity for the demons' previous defeat. Beryl uses force fields to separate the party and sends trolls with regeneration after them. Tama and Cedric defeat them with fire blasts and a life-draining sword respectively. Aria kills Beryl, but he stabs her with a poisoned dagger. The party rushes her to the town where a doctor explains the antidote requires an earth dragon eye. Tama rushes to the dungeon and fights the earth dragon from before. Realizing he cannot defeat it as he is now, he evolves to his next stage and becomes an enormous behemoth. ||||||
| 4 | "Awaken - Behemoth!" Transliteration: "Kakusei! "Behīmosu"" (Japanese: 覚醒！《ベヒーモス》) | Lee Dong-ik | Tetsuo Hirakawa | Shin Matsuo | January 25, 2025 (2025-1-25) |
| Tama mortally wounds the earth dragon, but runs out of energy and returns to cat form. He carries the dragon back to Lenard where the team extracts an eye and feeds it to Aria. As she recovers, she remembers being saved from demons by Alisha and her elemental cat. They return home and Tama goes to the dungeon alone, where he is attacked by a woman with fangs and claws, but escapes. Aria confides that she is tired of always being saved. She gets new armor from Vulcan and the three of them return to the dungeon. They meet the woman from before who has no name and wants to have sex with Tama. Aria takes pity on her and takes her in, naming her Stella. Aria and Vulcan need to teach her basic things like bathing. As Aria sleeps, Stella telepathically speaks to Tama and explains she was the earth dragon he killed, who reincarnated in a humanoid form and is now in love with him. Aria wakes up and says Tama is hers, but Stella refuses to give up. ||||||
| 5 | "Elf Girl & Dragon Girl" Transliteration: "Erufu Musume to Doragon Musume" (Japanese: エルフ娘とドラゴン娘) | Takashi Asami | Kan'ichi Katō | ROMANoV HiGA | February 1, 2025 (2025-2-1) |
| As they eat breakfast, Stella thinks that Aria is strong since she is Tama's master. Tama makes Stella promise not to tell anyone he is a behemoth. Vulcan makes Stella some armor and she chooses a massive sword and shield as her weapons. She demonstrates that she can turn her hands into dragon claws and grow a dragon tail at will. They explore the dungeon, but Stella keeps recklessly charging ahead. She is almost defeated by a roper until Tama saves her, making her calm down and agree to work with the others. As they bathe in a spring, Aria and Stella argue about who deserves Tama and get angry when Vulcan suggests they all share him. They return to the guild so that Arnold can register Stella as an adventurer. A man named Reiss asks for help protecting a shipment. Vulcan cannot come because she has a blacksmithing job. Stella is shocked to learn the shipment is the skeleton of her previous earth dragon body. ||||||
| 6 | "Girls of the Wandering Woods" Transliteration: "Mayoi no Mori no Shōjo-tachi" (Japanese: 迷いの森の少女たち) | Shigeki Awai | Toshiaki Satō | Shin Matsuo | February 8, 2025 (2025-2-8) |
| Before they leave, Arnold promotes Aria to Rank B. Reiss, Aria, Stella, and Tama transport the skeleton by wagon to his hometown of Gladstone. After fending off monsters, they make camp and Reiss gifts Aria some lily of the valley, his fiancee Eliza's favorite flower. He says the skeleton is for raw materials because a war is coming soon. A forest-like labyrinth emerges in their path, but they escape and reach Gladstone. Reiss thanks them and lets them explore the labyrinth. Voices lure them to some hostile apes, but after defeating them, the voices surrender and reveal themselves as the dryad Feri and the tiny fairy Lily. The two give them a potion and a key to a boss room. The group takes them in and they go to Gladstone, but must teach them concepts like paying for food. Reiss examines the potion and says it is Drop of Truth, a powerful truth serum. When he sees Feri and Lily, he is shocked and excuses himself. The group bathes and Tama nearly goes crazy when the others grope Aria. Vulcan finishes her job and rushes to Gladstone on foot. She is attacked by and defeats a skeleton, but hears a bell and sees some lily of the valley. The group returns to the boss room and defeats a torrent drake. They find a scroll that instantly gives Aria the ability to turn her daggers into holy blades. Feri and Lily are suddenly kidnapped. Reiss rings a bell and tells a portrait of Eliza that he'll be able to bring her back soon. ||||||
| 7 | "Undead on Approach Dark Tales of the Earl" Transliteration: "Semari Kuru Andeddo Hakushaku-ryō no Kuroi Uwasa" (Japanese: 迫りくるアンデッド 伯爵領の黒いうわさ) | Keita Nakano | Tetsuo Hirakawa | Takayuki Inagaki | February 15, 2025 (2025-2-15) |
| Aria, Stella, and Tama cannot find Feri and Lily, then Vulcan arrives and they fill her in. A butler says the Earl of Gladstone requests their presence. As they travel to him, Vulcan says she heard rumors of girls disappearing around Gladstone. The Earl, a fat and ugly man, asks the three girls to be his mistresses and tries to serve them drugged tea, but Tama neutralizes it. They interrogate him, but he doesn't know about Feri and Lily. The town gets attacked by skeletons. Vulcan guards the people while Aria, Stella, and Tama find Reiss summoned them with his bell and kidnapped Feri and Lily to drain their mana. He wants revenge against the Earl for killing Eliza and reanimates the earth dragon skeleton. They battle it and Aria destroys the skeleton with her holy blade skill while Tama rescues Feri and Lily. One of the skeletons reveals herself as Eliza and tells Reiss not to seek revenge, destroying his will to fight as the bell and the skeletons disappear. Reiss is arrested and sentenced to the guillotine, but Aria serves the Earl tea laced with Drop of Truth, making him confess that he and his butler raped and murdered several women including Eliza. The enraged townspeople turn on them. The Earl, the butler, and Reiss are all sentenced to life in prison. Feri and Lily have joined the party and they all bathe and argue who deserves Tama. ||||||
| 8 | "The Elf Girl Makes a Move" Transliteration: "Erufu Musume no Ohikkoshi" (Japanese: エルフ娘のお引越し) | Takashi Asami | Kan'ichi Katō | Yoshihiro Takamoto | February 22, 2025 (2025-2-22) |
| The party comes home and Arnold promotes Aria to Rank A and Stella to Rank B, but Vulcan turns down a promotion. Gladstone gifted the party a ten year supply of preserves, but they have no room to store them. Arnold suggests they move into a new house and they agree. That night, Tama learns his behemoth form has evolved, making Stella even more attracted to him. The next day, Feri grows a World Tree and Lily creates a Fountain of Life in the yard, but Vulcan warns everyone to keep them secret. Arnold says a monster in the dungeon has killed people, so the party enters and slays goblins and a massive troll. As the party bathes, Aria realizes the party is her new family and vows to protect them. Meanwhile, knights separately tell the emperor and Alisha that monster attacks are intensifying, possibly due to the demons. ||||||
| 9 | "Fated Reunion in the Imperial City!" Transliteration: "Teito e! Unmei no Saikai" (Japanese: 帝都へ！ 運命の再会) | Shigeki Awai | Toshiaki Satō | Fumikazu Satō | March 1, 2025 (2025-3-1) |
| Arnold tells the party that Emperor Geisel Auschra has summoned them, but Vulcan is nervous. They take a wagon to the imperial capital and are escorted to the emperor and Prince Julius. After the emperor thanks them for saving Gladstone, it is revealed that Vulcan knows them since she was once the royal smith and a veteran of the war against the demons. A demon ally named Lady Belzebuth, who can read minds, arrives. She says she needs help because four demons plan to unseal the 7th demon king, Mammon, and revive the God of Darkness. They have Vulcan forge new weapons, Julius train Stella, Belzebuth teach Feri and Lily new spells, and ask the retired Alisha to train Aria. Aria is starstruck to meet her again. During sparring, Alisha easily beats Aria with a wooden sword and Julius easily beats Stella with his superior skill, but they slowly improve. While they bathe, Alisha and Belzebuth reveal they are both married to the Grand Mage, who is from Japan and transported from Earth, but is busy and cannot help them. Alisha tells Tama she knows he is a behemoth, but will keep the secret. Eventually, the four demons are detected in separate locations. Cedric and his party will deal with two of them, but one is in Alisha's hometown of Alphes and one is in Ruine, the town the party lives in. ||||||
| 10 | "The Powers of Tama and Aria" Transliteration: "Tama to Aria no Mezameru Chikara" (Japanese: タマとアリアの目覚める力) | Yūji Kanzaki & Keita Nakano | Tetsuo Hirakawa | ROMANoV HiGA | March 8, 2025 (2025-3-8) |
| Alisha goes to Alphes alone while Aria's party and Julius go to Ruine. They meet Cedric's party (Cedric decided go alone) and enter the dungeon. After demonstrating their new skills and weapons on some monsters, Cedric's party is occupied fighting trolls while the rest meet the demon Vasaago. Vasaago summons a cyclops and orthus to fight the party while he fights Julius. Julius is quickly knocked out and Vasaago escapes to the demon realm. When the party starts losing, Tama has no choice but to transform into his evolved behemoth form. In Alphes, Alisha finds the demon Revi bathing. Revi turns into a dragon while boasting of her power, but Alisha effortlessly kills her. Aria and the others mistake Tama's form for a holy beast. When outmatched, the orthus and cyclops commit suicide to perform a powerful flamethrower and create a homing lance respectively. Tama matches the flamethrower with his own while Stella blocks the lance expecting to die. Aria awakens a new skill, Excalibur, and fires a holy blast that destroys the lance and the orthus' body. Tama reverts to his cat form. Back in the capital, Belzebuth says Vasaago's forces move towards Aria's home village of Lumines, after the Philosopher's Stone stored there. Everyone volunteers to defend it. ||||||
| 11 | "The Philosopher's Stone & the Secret of Lumines" Transliteration: "Kenja no Ishi to Rumirusu no Himitsu" (Japanese: 賢者ノ石とルミルスの秘密) | JOL-chan | Kan'ichi Katō | Hong Min-seok | March 15, 2025 (2025-3-15) |
| Everyone, including Arnold, sails to Lumines, but Cedric is still busy. They are greeted by the village chief Elvan, and a squad led by the Amazon Gusione and Aria's mother Leona. After the party meets Aria's friend Fionne and her elemental cat Leo, Elvan shows them the Philosopher's Stone is stored in a massive tree. Leona hosts the party and Aria is worried about her getting hurt, but Leona assures her that she became a warrior to defend the village. Gusione tries to steal the Philosopher's Stone, but Alisha unmasks her as a demon and kills her. Gusione's owl familiar escapes and reports to Vasaago, who opens portals to let his army invade the village. Alisha surrounds the village with a force field that kills the demons on contact, but Vasaago is uncaring and crashes his forces against it until holes are made in it allowing them to enter. After Julius makes a rousing speech, everyone charges into battle. ||||||
| 12 | "Sacred Blade & Beast" Transliteration: "Seinaru Yaiba to Seinaru Kemono" (Japanese: 聖なる刃と聖なる獣) | Keita Nakano & Takashi Asami | Tetsuo Hirakawa | Kin'ya Nakamura | March 22, 2025 (2025-3-22) |
| As everyone battles Vasaago's forces, Cedric arrives and saves Arnold from a sneak attack, then they fight together. Vasaago summons the dragon Nidhogg and rides it into battle. Tama takes his evolved behemoth form and Aria rides him to take the pair on. Vasaago gets past them, breaks into the tree, and has Nidhogg swallow the Philosopher's Stone before trying to ride it through a portal to the demon realm in the sky. Aria jumps on Nidhogg and tries to fight Vasaago, but jumps off when she notices Tama hesitating out of fear of hitting her. Tama and Nidhogg clash, then while still falling, Aria blasts them with Excalibur, vaporizing Vasaago and Nidhogg while leaving the Philosopher's Stone intact. Tama catches both while the demons retreat. Tama returns to cat form and everyone celebrates with a feast. Vulcan beats Howard in a drinking contest. Julius asks Stella to join his army, but is refused. Belzebuth praises Lily and Feri for their part in the battle and conjures exotic food. Alisha grants Aria and Tama the titles Sacred Blade and Sacred Beast. Upon returning to Ruine, everyone is praised as heroes. While the party bathes, Aria, Vulcan, and Stella beg Tama to take his behemoth form and have sex with them, horrifying him. The party later wanders as Tama narrates that they have many adventures ahead and he will continue to protect Aria and their friends. ||||||