Marriage Toxin, Vol. 11 by Joumyaku

Gero may be a master assassin, but he’s not exactly killing it in the romance department! Can marriage swindler Kinosaki help him find true love?

Poison Master Hikaru Gero is taking on his toughest assignment yet—getting married! Gero couldn’t be more clueless when it comes to dating, but thankfully, marriage swindler Mei Kinosaki knows everything there is to know about love. Together, this unlikely pair will do whatever it takes to get Gero hitched—even if they have to take on the entire criminal underworld in the process!

After accepting an unexpected job from Water Master Ushio, Gero and Kinosaki find themselves in the midst of the ancient and powerful fire masters! Ushio has been summoned for a sacrificial fight to the death, but when Ushio’s opponent is suddenly found dead before the match, Gero must help Ushio break free of the fire masters’ backward traditions once and for all!