A sympathetic character who's wreched, funless life is fleshed out, then they die.
A variation on the Sacrificial Lamb - here the character is so sad that it almost seems a blessing when they die. I need more examples, but one I remember is an un-named character from Halo Jones by Alan Moore who has had so many sex-changes they are neither male nor female, and as a result is nearly invisable - your attension cannot focus on it. Even rats don't notice it. This character dies to save the heros, and they barely remember it. This is an extreme example.