What can kill superman other than any kryptonite
Doomsday killed him
Magic is another thing except kryptonite that can kill superman. This is because he has a high vulnerability to magic and can therefore be killed by it. Again, lack of basic necessities like breathing, eating and drinking can kill him.
thor, the hulk,
Look up the series the death of superman. In it doomsday kills him.
A black hole. It would disassemble him particle by particle.
Hollywood is the only thing that can put a permanent end to Superman.
A nuclear missile. Or a black hole.