She failed to collect the relics so is she dead or what’s going on and could there be a chance she will betray the witness because of what is going on with house of salvation
Edit:(spoiler for spire of the watcher dungeon)I found out that she is alive in spire of the watcher dungeon
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My best guess is that Eramis will become a disciple of The Witness, and we'll see her return as a boss somewhere Lightfall and The Final Shape. I think she was out to get the relics under her own guise, possibly to save her house, but was distorted by the darkness, and could very well be tied to The Witness in one or more ways.