[SPOILERS?] A question about moon spy rewards.

[The_Stalker]

So one of my old friends got a vengeful revenant from moon spy, now I'am not completely sure about the drop chance on this or whether you have to complete all 3 vaults (most likely) to get it.  I just wanted some confirmation on this if it was true or not. 

[AldehydeBackhand]

Probably best to complete all three to maximize your chances.

I wanna thank you and your friend for confirming that it can be found on the moon. My determination has returned.