It's called death.
Somehow, he doesn't see it. He keeps talking – bragging – about how he could (and will) kill you.
Like you care.
You'd do almost anything to be dead. You've even tried killing yourself in the past. It didn't work. It never has. You hope it will someday. But, you know now, unless you kill this monster, no one ever will. Kill him, that is.
And you don't mind sacrificing your life for this. At least this makes it worth something.
So, here you are, facing each other, weapons drawn.
You both shoot at the same tie. You know you're going home. He's going into the bleak oblivion of the unknown.
It's called Death.