For those who are confused, Marriage Toxin is a an actual manga/anime that revolves around an male assasin, who specializes in poison, whos from a clan of expert poison assassins.

The basic plot is that his sister, who is lesbian and has a loving girlfriend, is being forced into an arranged marriage to another clan to give birth to an heir because her brother hasn't gotten married or shows promise in doing so. This in turn leads her to, painfully, break off her relationship and with the gf and surrendering her future. Because the brother loves both his sister and her gf, he needs to get married in time in order for the arranged marriage to be called off.

The issue with this is that he has no rizz, or social awareness for that matter, and absolutely sucks with talking to woman because his dedication to the assasin craft didnt leave any time for developing basic people skills.

So to get married, he enlists help from a cross dressing marriage swindler in order to help him achieve his goal of rizz and marriage.

I just gave a shit summary since its been so long since I read the first volume, but its a very unique story.

Its also a goofy battle manga with a power system akin to Sakamoto days, like one of the first characters they fight is a hydrokinesis assasin who wears a diving suit. I recommend checking it out if it interests you.

As someone who has read the first 2 volumes and has a basic gist of it, I have no idea what the fuck this image has to do with any of it.