The hero in my story succeeds in destroying the villain, but not without paying a hefty prize. Not only will he die, he will stop existing and can't be brought back, at all. It's like he never existed to begin with. Nobody will remember him.
Ghosts exist in this world, but the afterlife is kept vague on purpose. Nobody really knows what comes after "crossing over", and the ghosts are really just part of a curse, not "natural" or proof that there is something after death.
The point is, dying in itself is already bad enough, as you don't really know what comes afterwards, despite the existence of ghosts. However, the hero has a fate even worse than that, having his entire existence completely erased.
I fear this might be too much of a gut punch for readers/players, as I already put him through a lot... A LOT... of horrible stuff before that, and I get the feeling most people would want me to cut the hero a break at this point.
The main point is to highlight how truly selfless the hero is, as he knows full well about the consequences, and how nobody will be able to remember his heroics, and still decides to do it. It's the only way to stop the increasingly more powerful villain. He was still selfless before that, but this is more of an extreme level up to his selflessness.
I kinda want to do this, but I also kinda don't want to. I'm very undecided and I'm leaning towards giving him a less harsh fate and have him just die, so at least there is a chance he has peace in the afterlife. How should I go about this possible plot thread that ends my story?