Talk:Ainz Ooal Gown/Abilities and Powers/@comment-26930675-20160905170717/@comment-29196789-20160905220227

If you're going by the web novel, Ainz actually mentioned the Greed Kings' flying base after coming to the New World, when he thinks about guilds that rival Ainz Ooal Gown in power. So undoubtedly they were level 100, and on top of that, among the best players in all of Yggdrasil.

This can change in the LN of course, but Ainz specifically cautioned Albedo and probably the rest of the guardians to stay away from the floating city. It's not a stretch to imagine that it's because he knows of their actual guild, and their power.