RenRen's manga / #Mermaid(2)

Seme is a low-time exorcist. He can see spirits but does not really exorcise them. Uke was born with the mermaid mark and eye because his mother drank mermaid bones to stay alive. He was treated like shit by everyone until a kind hearted tattooist took him in, tattooed over his scales to make them even more beautiful, and told him to live for he is his masterpiece.

Merman x Human. The human can't deal with the loneliness that comes with being immortal (bc he's a merman's bride) and always try to find ways to die. However, finding out that the merman is the last of his kind holds him back because he realizes if he dies then the merman will be truly alone for eternity (merfolks only have one partner their whole life, and if that partner is a human woman, once a child is born, the merman/mermaid will die)