When Superman Died

If you’re talking about the time he was killed by Doomsday, he wasn’t actually dead.

His heart had stopped beating, but he was actually simply in a kryptonian coma like state.

Both the doctors treating him and Superman himself didn’t actually know he could do that.

He would likely have died eventually, but fortunately the Eradicator (a kryptonian artifact introduced in a previous story) was aware of this quirk of kryptonian biology,

and after Superman was buried the Eradicator broke into his crypt and took him to the Fortress of Solitude, where he placed him inside a regeneration chamber to heal his wounds.

Depends on the version. If we are talking about the version of Superman from Rebirth, who’s also Post-Crisis Superman,

he can’t really die. First, the Universal Death told him she couldn’t get him because he was above Death and it was pissing her off.

Secondly, Superman Prime One Million (or Gold Superman Prime) is actually the Post Crisis version of Superman who lived for a million years.

Doomsday “killed” Superman but the sun brought him back. 

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