Marriage Toxin is a high-octane action-romance manga by Joumyaku and Mizuki Yoda, serialized on Shonen Jump+ since April 2022. The story follows Hikaru Gero, a skilled assassin from the Poison Clan, who must marry and produce an heir to preserve his family's legacy. To navigate the complexities of romance, he enlists the help of Mei Kinosaki, a cross-dressing marriage swindler with a knack for matchmaking. Together, they embark on a journey filled with intense battles, unexpected alliances, and a quest to find true love amidst the chaos of their dangerous world.