Information on the PVE game can be found at the following locations:
Fandom Wikia page for Age of Empires Online
This mostly has information on the Egyptians and Greeks fully fleshed out, with the quest info for anything that came out after Launch "needing attention".
Still, it is a pretty good resource for finding info on the PVE game's quests, items, and other content.
An online database of the game's content before the 2014 shutdown.
A more complete capture of the game's information at Launch, but missing most information on the game by it's end.
IGN guide for Age of Empires Online
Another resource for info on the game at launch, doesn't include info for any civs besides Greeks and Egyptians.
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