I have done research and Xur is agent of the nine. There is nine iron lords [indicated in the iron lord lore] and for some reason Xur has not yet made an appearance at the Iron Temple.
So, Xur has something to do with iron lords.
The stranger, talks to someone on "a strangers call" mission. She gave us her rifle, which doesn't look like anything but the no time to explain, which is an exotic
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Xur will never be at the Iron Temple because PS3 players won't be able to get to him.