4N-C3 was last detailed to be in RESEARCH of Sanctum Beta, presumably released due to the progress they were making on the specimin.
As likely a creation of longevity, 4N-C3 may still exist in this realm. Its abilities of mimicry may have allowed it to be the Emerald Cloaked Figure Find that Emerald Cloaked Figure.
We must scry on 4N-C3 to confirm its existence in our realm, and perhaps, find it.