User blog comment:PerhapsTheOtherOne/A New Theory on the Legendary King Ghidorah/@comment-25285745-20141130165949/@comment-25285745-20141130213943

I don't recall King Ghidorah even being in Godzilla: Ongoing. Keizer Ghidorah was in it, and he was an alien of some sort, possibly from another dimension. Kingdom of Monsters almost established King Ghidorah as his GMK version, but this was retconned in Rulers of Earth, where King Ghidorah (as Mecha-King Ghidorah) flies of into space "in search of other members of his kind," implying that he is a space monster and is related to Keizer Ghidorah.