Temple 1

Temple 1 was a Warforged who cared for the temple of Ytaru which concealed the entrance to Ginaron. At some point prior to the party's arrival at Ginaron, he was awakened from suspended animation alongside another warforged (presumably named Temple 2) and either at this time or between it and the party's arrival was possessed by Epsilon.
Epsilon then used a helpful "C3PO-like" persona (possibly based on Temple 1's pre-possesion personality) to gain the party's trust and have them escort him to the Controller, at which time he took it over and used it to overload Ginaron's portal, leading to a wave of Astral Energy, afflicting all biological lifeforms in the vicinity with Astral Plague.
Epsilon left in Temple 1's body via a dimension door, and continued to use it until Polaron, when he abandoned it in favour of a magma sifter. Upon discovering the vacant body, Little One made very sure theat it would never be usable again.