(Last chapters winner was yet again so hard to choose, but I decided to pick --drowninglessons because I thought it was funny 'calloused hand' but then it got sad.
Your OTP are peculiars (also known as syndrigasti). They have peculiarities, powers like having super strength, or being lighter than air, or bringing back the dead for brief periods of time, or being invisible.
Peculiars in the universe are viciously hunted by invisible monsters known as "hollowgasts".
Person A of your OTP has the peculiarity of pyrokinesis, able to create and control fire with their mind. Person B of your OTP has a very rare and important peculiarity: they can see the hollowgasts. Even better, they can control and talk to hollows.
Person B escapes war from their country and goes to a children's home, full of other peculiars, where they meet Person A. After a short time, they fall madly in love, but their is more war going on, and Person B valiantly decides to leave to fight.
Along the way, Person B becomes close friends with a man who is interested in B's peculiarity, as it is vital. He steals part of B's peculiar soul, and B loses the ability to talk and control the hollowgasts, though they could still see them.
Feeling shame for the loss of their peculiar soul, B leaves for a different country. They start a family with someone new. When they still receive letters from A asking why they won't write, they reply with a simple photo of themselves, holding their own child, and saying "this is why."
A and B never meet again, though still madly in love.
How does A react to the departure of B, or the sudden shock of finding out that B moved on? Are there any more tragedies to their story? What happens next? The best comment wins an honourable mention next chapter (it only counts if you vote on this chapter!)