How would you make it?
I would go back in time before the 1st game and show how the ancients lost the first time and where they came from. Always thought they could include
ancient civilizations like atlantis in it and show how it was destroyed by magic or somehow incorporate the ancients becoming the fall of those civilizations.
some of the possible settings:
pre hindu civilization, (the wars in the ancient hindu texts) - imagine shooting lightning arrows and flying a vimana
egypt ( perhaps the pyramid was a machine that amplified magic,) those gods could have actually existed and worked for the ancients
ancient babylon, - always wanted to play a game that could recreate how this city could have looked like.
aztec civilization (human sacrfice anyone? the mayan calander )
crucifixion of christ (perhaps jesus was chosen to fight the ancients and had his own book but ancients won and ended up rewriting history)
thats all I can think of now.