When I said "Stated Gods" I ment like entitys. The Dragon God's are not.
And I'm pretty sure all Greek God's were immortal forever, and could not even die by a weapon. Norse God's were capable of dying. The Greek's had the river Styx to bathe in (like Achellies, but he was the Son of a God and a human, so he had to be bathed in it to have immortality). The God's were born with immortality, but I'm just guessing that only their parents could destroy them, in other word's the Titans and Kronos, but even then they still did not die, only Zeus had to kill Kronos and then Hades/Posideon came out.