Once, on a distant planet far in the past, two experts existed.
These two experts were both old monsters who'd exhausted the majority of their lifespans, and in their final moments, these two clashed constantly.
On one side was a man who craved life. He worshipped immortality and did everything he could to stave off death, even using heinous methods to steal the vitality of others to sustain himself.
On the other side was a man who accepted mortality. He understood that death would eventually come for anyone who had yet to step onto the path of Godhood, and he didn't reject it. Rather, he welcomed the end of his life cycle, as it would only signify greater things for the future.
These two experts stood on opposite sides, and their clashes weren't merely using words. They constantly battled until their final moments, when they stood together to finally determine which of them was correct in their thinking.