A power or ability with no explanation. Thats different from a state of being or lineage. Everything has a source. To come from nowhere is not random either since random has a source too. Then again it could be fine if its creationism. Like if your character was cosmic or beyond. Everything has a frame of reference. So it depends on the explanation.
Okay I see. It’s not that the hero doesn’t have an explanation on their power, it’s how they got it. The easier they get it, the less relatable they are to the audience. The less flaws they have, the less the audience empathizes.
Superman is someone we like to aspire to but as a character he’s pretty boring. He’s never really in any danger. There’s no fear or suspense. His life is pretty perfect.
I think people like to hear and read about heroes overcoming difficult trials and odds. You can’t have that when the hero is good at everything.
Spider-Man is pretty powerful but very relatable. Outside his powers, his life is hard. He has finance issues. Girl issues. He has to take care of his elderly aunt. Yet he still finds a way to save NYC. It’s why he’s so popular. We can understand his struggles.