Gonna be the Twin-Tail!!

Plot

High school boy Soji Mitsuka is obsessed with twintail hair. He meets a mysterious girl named Twoearle, who came from a parallel world to the planet Earth. When monsters appear and invade Japan, they feed off "attribute strength", the spiritual energy of humans. Twoearle entrusted Soji with Tail Gear, imaginary armor initiated by powerful twintail attributes. This allows Soji to transform into a girl and twintail warrior (ツインテイルズ関係者, tsuinteiruzu kankei-sha) branded Tail Red.

Characters

Twintail Warriors

Soji Mitsuka (観束 総二, Mitsuka Soji) / Tail Red (テイルレッド, Teiru Reddo)

Soji (male) Voiced by: Nobunaga Shimazaki (Japanese); Austin Tindle (English)

Souji (female)/Tail Red Voiced by: Sumire Uesaka (Japanese); Bryn Apprill (English)

A high school boy of Yōgetsu Private Academy obsessed with pigtail hairstyles. He later meets a scientist girl named Twoearle arriving on Earth. When galactic monsters invade Japan, Soji receives a bracelet from Twoearle and becomes a twin tail warrior named Tail Red. Due to his alter ego being a celebrity, Soji becomes the leader of the Twintails. His weapon is Sword of Fire, Blazer Blade (炎の剣ブレイザーブレイド, Honō no Ken Bureizā Bureido). In volume 4, he gained two power-up forms: Riser Chain and Faller Chain. He later gains Ultimate Chain, after regaining his Twintail Elémera, which he lost to Tyrannoguildy.

Aika Tsube (津辺 愛香, Tsube Aika) / Tail Blue (テイルブルー, Teiru Burū)

Voiced by: Yūka Aisaka (Japanese); Sarah Wiedenheft (English)

A high school girl and Soji's friend. She has a complex with a flat chest on her body. She dislikes Twoearle for teasing her. Aika becomes a Twintail warrior and joins the team. She is a martial artist raised by her grandfather. She is known as Tail Blue when she transforms, and her weapon is Spear of Water, Wave Lance (水の槍ウェイブランス, Mizu no Yari Weibu Ransu). She also gains Eternal Chain.

Erina Shindō (神堂 慧理那, Shindō Erina) / Tail Yellow (テイルイエロー, Teiru Ierō)

Voiced by: Chinatsu Akasaki (Japanese); Mikaela Krantz (English)

The student council president of Yōgetsu Private Academy. Known as Tail Yellow in her transformed state, her weapon is Gun of Lightning, Vortex Blaster (雷の銃ヴォルテックスブラスター, Kaminari no Jū Vorutekkusu Burasutā). She is a closet masochist and exhibitionist, and gets aroused when she meets Soji. While being a Twintail warrior, she becomes a reckless fighter due to her maschostic ways. She is the only one of the twintails who at first could not use her power because of her denial, until she accepts it. Erina's twintail warrior form makes her whole body look a lot older and has a more well endowed figure. She gains Absolute Chain.

Others

Miharu Mitsuka (観束 未春, Mitsuka Miharu)

Voiced by: Hiromi Igarashi (Japanese); Jennifer Green (English)

Soji's widowed mother and the owner of the restaurant Adolescenza (アドレシェンツァ, Adoreshentsa). She is aware of her son's identity and supports him as she dreamed of being in a position. She allows Twoearle to stay with Soji.

Mikoto Sakuragawa (桜川 尊, Sakuragawa Mikoto)

Voiced by: Mao Ichimichi (Japanese); Michelle Rojas (English)

Erina's maid with an outstanding physical ability despite her job. At times, she works part time as a PE teacher for Yōgetsu Private Academy. She usually slips marriage registration forms in the boys' test slips with her name on them, or having Soji sign his name on it. It is clear that she is desperately looking and marrying someone before reaching 30.

Mega Neptune Mk. II (メガ・ネプチューン = MK.II)

Voiced by: Yukari Tamura (Japanese); Tia Ballard (English)

Anko's robot partner. Due to her long name, Anko calls her Megane (Japanese for glasses) for short which she dislikes.

Twin-Tail God (ツインテール合同, Tsuintēru Godo)

Voiced by: Shuichi Ikeda (Japanese); Kent Williams (English)

An imaginary being within Soji's subconsciousness. He helps him restore his body.

Strawberry Twin (ストロベリーツイン, Sutoroberī Tsuin)

Voiced by: Rie Kugimiya (Japanese); Felecia Angelle (English)

Ultimegill

Ultimegil (アルティメギル, Arutimegiru) is an organization of phantom-monsters called Elemelion who travel through different worlds, seeking a variety of "attributes". Although they are enemies of humanity, the majority of them are rather silly and comical and behave much like otakus, often admiring cute girls, collecting dolls, and even adoring the twintail heroines. Having discovered Earth is rich in "attributes", they colonize and make plans to conquer Earth. Members include:

Dragguildy (ドラグギルディ, Doragugirudi)

Voiced by: Tetsu Inada (Japanese); Chris Rager (English)

The leader of the Ultimegil with a twintail fetish.

Lizardguildy (リザドギルディ, Rizadogirudi)

Voiced by: Tesshō Genda (Japanese); Cris George (English)

An Elemelion soldier with a doll-holding girl fetish.

Turtleguildy (タトルギルティ, Tatorugirudi)

Voiced by: Takaya Kuroda (Japanese); Greg Ayres (English)

An Elemelion soldier with a bloomer fetish.

Foxguildy (フォクスギルティ, Fokusugiruti)

Voiced by: Toshihiko Seki (Japanese); Eric Vale (English)

An Elemelion soldier with a ribbon fetish.

Swanguildy (スワンギルディ, Suwangirudi)

Voiced by: Nobuyuki Hiyama (Japanese); Aaron Roberts (English)

An Elemelion soldier with the swan attached to the front face.

Media

Light novels

Gonna be the Twin-Tail!! began as a light novel series, written by Yume Mizusawa with illustrations by Ayumu Kasuga. Mizusawa originally entered the first novel in the series, originally titled Sore wa, Twintail no Isekai (それは、ついんてーるの異世界, Sore wa, Tsuintēru no Isekai), into Shogakukan's sixth Shogakukan Light Novel Prize in 2011 and the novel won the judge's prize. The first novel was published by Shogakukan on June 19, 2012, under the Gagaga Bunko imprint, and fourteen novels were released on December 19, 2017.

The 16th volume of the series was released in October 2018, and the 17th volume on March 19, 2019. The series ended with the 21st volume (22nd overall) on November 18, 2022, while the first volume was released in English on Shogkukan's novel app on January 23, 2025.

Manga

A manga adaptation titled Ore, Twintail ni Narimasu π (俺、ツインテールになります。π, Ore, Tsuintēru ni Narimasu.; Gonna be the Twin-Tail π) by Ryōta Suzuki was serialized in Square Enix's Monthly Big Gangan magazine from August 25, 2014 to June 25, 2015, and was compiled into two tankōbon volumes.

Anime

An anime television series adaptation produced by Production IMS and directed by Hiroyuki Kanbe, aired in Japan from October 9 to December 25, 2014. The opening theme is "Gimme! Revolution" (ギミー！レボリューション, Gimī! Reboryūshon) by Maaya Uchida. The ending theme is "Twin-Tail Dreamer!" (ツインテール・ドリーマー！, Tsuintēru Dorīmā!) by Sumire Uesaka, Yūka Aisaka, and Chinatsu Akasaki. Both singles for the themes were released on October 22, 2014. The anime was licensed by Funimation in North America, and in the Middle East, North Africa, and Europe (excluding North America, Scandinavia, and United Kingdom) by Crunchyroll, and AnimeLab in Australia and New Zealand.