Osiris if I'm not mistaken, is obsessed with the vex. So much so, when he was exiled, he took his ideals and followers to mercury to live on a vex machine world. Again, I don't have the grimore behind it like I should, so if I'm wrong, I'm wrong, and my bad for asking a bad question. -edit- if you get the exotic question..... I dub thee the one desticle to rule them all... (meaning, I've not the slightest clue.. I hardly speak English well enough to know what Latin/greek/ancient languages bungie took those words from)