On the "Hacking the planet" adventure on Nessus, its heavily hinted towards the end that he is stuck in the vex network with no way to get out. Failsafe talks to him, and (we assume) Osiris tells her about a lot of vex intel he has learned. However, it could also be Praedyth...? And to your question of if he is evil...I'm no lore master, but I would say no, he is not. Osiris was originally recommended by Saint-14 himself to be leader of the vanguard like Zavala, and he was also the apprentice of the speaker. The reason he was exiled was partially because he was obsessed with the vex, yes, but it was much more than that. Osiris questioned the very origins of Guardians. He wondered why we lose our memories, and he speculated that guardians have a predisposition towards following the orders of others without questioning them. He also asked why we shouldn't be studying the darkness as much as the light, because it's a "know your enemy" kind of thing. The final straw was when Osiris called the speaker out on his BS, and that's why he was exiled. However, we know now that Osiris was right all along, because the speaker "never said the traveler actually speaks to him." So yeah. This is all from memory of what I read a year ago, so take it with a grain of salt. But I would say he wasn't evil at all, but just too curious about his origins for his own good. Edit: found [url=http://planetdestiny.com/osiris-lore/]an article about it right here.[/url] Apparently, in addition to what I already said, he was also leading Guardians away from their duties of protecting the last city and instead to gain information about his own goals. Osiris was also practicing thanatonautics (killing himself and reviving, because he was a Sunsinger), and looking for the Ahamkara which is [b]VERY[/b] forbidden. Edit 2: Grimlock 205 also had some very useful info as to why he was exiled: [quote] Osiris was exiled not because he questioned the speaker(that strained their relationship, but didn't warrant an exile), but because he was dividing the guardian population and leading guardians astray. Not only was he studying forbidden things, but he was indirectly inspiring guardians to abandon their responsibilities. Hunters started to stop helping refugees beyond the city, titans were looking to explore strongholds like VoG, and warlocks stopped researching the light. Thus he was exiled. This is important: It is unknown if the speaker exiled him, or if Osiris [i]exiled himself[/i]. Osiris knew of the harm he was causing and may have left on his own. This is reinforced by how the speaker seemed to want to talk Osiris. It didn't seem like he harbored any grudges.[/quote]