This is my theory on The Nine (long message alert) I believe The speaker is evil and he secretly wants to destroy us from within. The speaker doesn't want too much information to be leaked about the darkness. The reason I think this is because the speaker exiled guardians who have decided to devote their lives on studying the darkness e.g Toland and Osiris were exiled from the city for knowing too much about the hive and the vex. The speaker just wants us to keep to his orders by simply seeing the darkness as evil and we should destroy it. Now, Let me ask you something...why would The Speaker exile someone from the city just because they know too much about their enemy? Isn't knowledge power? Wouldn't you be a good asset to your army if you know a ton of information about the enemy? Of course you would. Now for my next question...why did the speaker exile Osiris and Toland? Nobody knows why... Basically the speaker is hiding something. He has a big secret he doesn't want anybody to know. My theory is that he is evil and we are fighting for the wrong cause. The speaker is looking to destroy us from within. Now this is where I (finally) start talking about who I think The Nine are... The Nine are 9 powerful guardians who were exiled from the city because the speaker had his suspicions that they would find out about his evil secret. They knew too much about the darkness and were beginning to unravel the speakers dark secret so they got exiled. Once they were exiled, the 9 of them all formed a group. They called themselves The Nine and are fighting for what's right. They are set up in a different location. maybe mercury, Venus or maybe that location you were talking about in which we have to access through the reef. Since they are exiled from the city they ordered an agent called Xur to supply the guardians of the city with exotics to help us in our fight. Nobody knows who Xur is, not even the speaker. The speaker just sees him as help. So Xur can just remain being that unknown shady guy with exotics. The Nine are still helping us even though they have been exiled from the city. This is my theory on The Nine :)