So you walk in to finish oryx once and for all ( take in mind that what ur currently doing is not a Raid just yet, more like a hard missions) and u fight him and all, then he gets weakened and summons this taken warlocks ghost and he spawns and oryx is protected by a barrier bubble. And you fight him he uses every subclass and then you see other ghost shells of other guardians and u fight them, turns out they are fallen guardians lost in time from VOG and u get new quest to find it about it and like that vex are involved into this (but the guardians are weaker than the warlock) and it goes on until you defeat the warlock and oryx disappears (that's when the raid unlocks) then cayde or someone else comes into the comms and says that, that warlock was like Osiris or something and you bring the ghost she'll to the tower and u unlock Osiris Cus u relieved him of the taken curse and he becomes available at the reef or tower replacing brother Vance or maybe with brother Vance. Then you procced to oryx and idk how the raid would go lol. - Join kik chat #towerplaza for Destiny chat!