i was playing homm3 and lo and behold i find this monster called a GOG, had to laugh to myself.

i found them on the first scenerio of the restoration of erathia campaign. good stuff.

Yup! They're in MM7 as well. I can't remember if HoMM4 or MM8 have them.

Yes, they are in Might and Magic VIII.

I wouldn't put it quite like that. They were actual kings mentioned in the Bible who lived around the time of the Israelites' exile in Babylon. The prophet Ezekiel is the first to mention these kingdoms (an unrelated[?] "Magog" is one of Japheth's sons mentioned in Genesis).

Later, those names are used symbolically in the book of Revelation to represent all human government and institutions that oppose God. Even then, Revelation only uses the names once - Revelation 20:8.

It's probably because of the latter reference (in Revelation) that those names took on an air of mystery and then were used in fantasy literature/games/etc.

I didn't know the details, thanks for sharing that with us.