Marriagetoxin

Hikaru Gero can kill you with poison before you even notice he's in the room. What he absolutely cannot do is talk to a woman without it being a disaster. As the heir to one of the five most powerful assassin families in a world where Poison Masters have perfected the art of killing for centuries, Hikaru has zero social skills outside of, well, murder. The problem is, his family needs an heir, and if Hikaru doesn't get married, his sister gets forced into bearing one against her will. His solution? Spare the life of his current assassination target, a cross-dressing marriage swindler named Mei Kinosaki, in exchange for dating coaching. An elite assassin learning how to flirt from a con artist he was supposed to kill, that's the dynamic, and it works way better than it has any right to. The action hits hard thanks to Bones Film handling production, and the comedy comes from Hikaru being genuinely hopeless at anything that doesn't involve lethal toxins. If you liked the found-family chaos of Spy x Family or the way Assassination Classroom mixed genuine threat with humor, this scratches a similar itch. There's also a bit of that Kaguya-sama energy in how the relationship stuff plays out, strategic, awkward, and weirdly high-stakes. It's a shounen that balances clan politics, assassin throwdowns, and the quiet tragedy of someone who never learned how to just be a person. Coming in 2026, and honestly the premise alone earns a spot on the watchlist.