You were horrifically killed in an alternate timeline
As a child, you were rescued from a demon attack on your town by demon hunters. Ever since, you've dreamed of becoming one yourself. In an alternate timeline, you did. But it didn't last long.
Like so many others who become an adventurer, your life was cut tragically short. Your death at the hands of demons caused your brother, Nathan—an aspiring musician—to give up on his musical dreams and become a demon hunter. This was a long, long path that ultimately led to him becoming The Plague, the ultimate embodiment of chaos and destruction. Not even the gods stood a chance at stopping it. It travelled from realm to realm—growing more powerful with each person it killed—and snuffed out almost all known life. Once it ran out of things to kill, its energy slowly radiated away until it too died. And you were the seed to this universal tragedy.
Now, somehow having this knowledge before you've even started adventuring, you're faced with a moral dilemma. Should you continue with your dream of becoming a demon hunter knowing what will happen if you died? Or should you give up on your dream for the greater good of all life?
Keep in mind that just because this happened in an alternate reality doesn't mean it'll happen again in yours. You aren't destined to die unless you literally repeat everything you did in the previous timeline exactly the same way. Just know that your brother causing the end of the universe after your death is a possibility.
Do you pursue your dreams?