Copperplate unmasked to reveal that she was Nemesis Node Wendy, in a mutually beneficial symbiotic relationship with their world's ADA. Nemesis ADA had renounced her alliance to the N'zeer after seeing what they wrought during the ingression, and joined Nemesis to combat them. But moonlighting as the Tethered hand had been kept a secret even from Nemesis. The Tethered Hand was never held against her will, that was all a carefully cultivated fiction to encourage competition between Osiris Node and Nemesis Node. To encourage both worlds to make more headway faster on assembling the Tesserae and tuning the Tessellation.