>>281981277 (OP)
The sword is meant to be pulled by the legendary hero who will save the world from a great darkness. The Demon King was the greatest threat that the world knew at the time, but that doesn't mean he's the greatest darkness that the world will ever face.
The sword is waiting for a more epic, greater threat to the world. Count yourself lucky that it happens in the future, and not in your lifetime.
There will come a time when the sun no longer rises, when humanity is reduced to a single fortress city whose defenses are worn down battle by battle every day. A world where demons have come into the fullness of their power, and mankind's great works are empty shells that dot the ruined landscape. A world where hope and courage are a precious, dwindling resource.
That is when the hero's sword is meant for.
