Marriagetoxin

• Ja Kanji — マリッジトキシン • Ja Romaji — Marijjitokishin • Genre — * Action • Romantic comedy

• Type — manga • Author — Joumyaku • Illustrator — Mizuki Yoda • Publisher — Shueisha • Imprint — Jump Comics+ • Magazine — Shōnen Jump+ • First — April 20, 2022 • Volumes — 18

• Type — tv series • Director — Motonobu Hori • Writer — Kimiko Ueno • Music — * Taisei Iwasaki • Yuma Yamaguchi • Studio — Bones Film • Licensee — Crunchyroll • Network — FNS (Kansai TV, Fuji TV) • First — April 7, 2026 • Episodes — 13

• Portal — yes stylized in all caps is a Japanese web manga series written by Joumyaku and illustrated by Mizuki Yoda. It has been serialized in Shueisha's Shōnen Jump+ app and website since April 2022, with its chapters collected in 18 tankōbon volumes as of July 2026. Viz Media licensed the series for English release. An anime television series adaptation produced by Bones Film aired from April to June 2026. A second season is set to premiere in January 2027.

Hikaru Gero is a young man from the Poison Clan of professional assassins, which has been in existence for hundreds of years. Because he deals in the dark side of society and has never lived a "normal life", he considers himself to have no prospects with women and has no interest in marriage. However, one day, the Poison Clan states that if Gero does not marry and produce an heir to carry on their lineage, they will force his younger sister into bearing a child against her wishes. Wanting to save his sister from such a fate, Gero asks one of his assassination targets to marry him. Though Gero’s offer is turned down, the aforementioned target, cross-dressing marriage swindler Mei Kinosaki, agrees to train Gero on how to date and to appeal to women, so that Gero can fulfill his goal of finding someone he truly wants to marry.

• Hikaru Gero: • Gero is the designated heir of the Poison Clan, one of the Five Great Families of assassins. Under pressure to produce an heir to the Poison Clan, he vows to protect Kinosaki in exchange for his help in finding a bride. • Mei Kinosaki: • Kinosaki is a marriage swindler who has made countless men and women fall for him. Although Kinosaki dresses as a woman and is perceived by others as female, he is actually male and claims to be irresistible while dressed as a man.

• Kyoko Himekawa: • A thief who returns stolen art to its rightful owners. • Shiori Ureshino: • A kind but shy college student who will one day take over her family's party supply company. • Kimie Arashiyama: • The Hamster Master, whose family is a branch subordinate to the Beast Clan. • Chinatsu Akakura • A "protector" who has skills similar to the assassin clans, but more useful for defense, as they have not specialized. Her weapon of choice is a metal-alloy barrier tape. • Makoto Himi • Ureshino's friend, who can change her attitude from meek and mild to aggressive to suit the audience. Her father Yukio has made many sacrifices after the death of her mother. • Shizuku Ushio: • The Water User, who comes from the Fire Clan.

• Piichi Nakagawa: • The Hit Man Hunter, an "ordinary guy" who has great talent with a knife. He wants to open a cafe with his girlfriend Marin and has decided to kill the assassins, starting with the Beast Clan, because he feels his potential patrons would not be able to dine in peace otherwise. • Akari Gero: • Sister to Hikaru Gero. Pressured by the family to produce an heir, she begins to give in, but her brother takes on the task himself, so she can continue living happily with her girlfriend. • Toshiki Hanamaki • Isamu Yūsen • Erina Zao • The only daughter of the head of a criminal organization; after he left, he was betrayed by his former colleagues and killed, and they now pursue Erina. • Genya Naruko:

• Toshiro Dogo (Beast) • Head of the Beast Clan and one of the Five Great Families. His animal partner species is a bat. • Tonako Dogo (Beast) • New head of the Beast Clan and sister of Toshiro. Her animal partner species is a wolf. • Toshiki Hanamaki (Bug): • His family is a branch subordinate to the Poison Clan. He is married to Anna Kawakita. • Tsunagi Hayato (Needle) • His family is a branch subordinate to the Poison Clan. • Nagihiko Kushima (Spear) • Killed by Piichi; he was infamous for indiscriminate killing. • Byakko (Bear) • From a family subordinate to the Beast Clan which are shunned as the "impure masters" because they skin their bear partners rather than control them. • Kazuma Kannawa (Wind-Wheel) • The Kannawa family was thought to have died out before a trio of siblings, led by Kazuma, were hired to capture Erina Zao. He has a sister (Mitsuba) and brother (Kojiro). • Reiji Sakazuki (Ghost) • He uses weapons and belongings possessed by ghosts, either forcing humans to attack with cursed weapons or debuffing their abilities with spiritual mementoes.

Marriagetoxin is written by Joumyaku and illustrated by Mizuki Yoda. The manga was officially announced by Shueisha on April 11, 2022, and began its weekly serialization for free on the Shōnen Jump+ app and website on the 20th of the same month. Shueisha also simultaneously publishes the series in English for free on its Manga Plus platform. In June 2023, Viz Media announced that they licensed the series for English release under the name Marriage Toxin.

These chapters have yet to be published in a tankōbon volume. • Chapters 163–176

An anime television series adaptation was announced on October 1, 2025. It is produced by Bones Film and directed by Motonobu Hori, with series composition and scripts handled by Kimiko Ueno, characters designed by Kōhei Tokuoka, who also served as chief animation director, and music composed by Taisei Iwasaki and Yuma Yamaguchi. The series aired from April 7 to June 30, 2026, on the brand new Ka-Anival!! programming block on Kansai TV, Fuji TV, and their affiliates. The opening theme song is "Kill or Kiss", performed by Yurina Hirate, and the ending theme song is "Shake Na Baby", performed by AKASAKI. Crunchyroll is streaming the series. Muse Communication licensed the series in Southeast Asia. A second season was announced following the airing of the final episode. It is set to premiere in January 2027 on the same programming block.