My personal belief is that oryx is still alive and he could be the one pulling the strings and contacting uldren
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Oryx. Is. Dead. The only way he comes back is if Savathun or Xivu Arath [i]recreate [/i] him by manifesting his defining character trait: his curiosity. This is how he brought them back after killing them in acquiring the power he needed to slay Akka. Xivu Arath might be inclined to do this. But Savathun has always wanted Oryx out of her way, and is unlikely to do anything that brings him back unless her own survival is at stake.