Death
In the Marvel Universe, death is not just inevitable, but it's also a character. Death takes many forms, but is often seen as a female or skeleton wearing a purple robe. Born when the universe was created, Death is the void of life and eventual end of all things.
Death has its lovers, most notably Thanos, who once killed half a universe to win its love. It kinda worked - Thanos and Death went to TGI Friday's for dinner and drinks, but Death wouldn't let Thanos past second base.
