Originally posted by MattDay
doomsday's kryptonian dna allows him to damage superman, kinda like a natural kryptonite if you will, they bypass eachothers invulnerability, like the fight with zod, the rest is correct
Wrong.
Superman has an invulnerability composed of two elements:
-His denser than human physical structure.
-His skin-like bio aura.
Like Thor he has a body which is denser than that of a common human so he has resistance both physical and energy attacks to an extraordinary extent.
His bio aura grants him addictional protection but this doesn't mean he cannot be hurted.Beings with sufficient strength to bypass his defenses, which have a limit, high but still existent, or energy attacks of sufficient power can cause him pain, injuries, blood losing and death.
Magic seems to pass through Supes bio-aura and damage him, if his body wasn't denser than human, he would have been murderer from a long time.It's his denser structure which saves him when he gets hit from the likes of Shazam lightning or something like that, but anyway a sufficiently powerful magical assault will slay him down, quicker than physical force or other energy attacks, unless the energy attacks are of really high magnitude.