| Our records on this topic are somewhat incomplete. |
The Dark Ancients are a group (race?) of body-hopping energy beings who used to be warforged. They possess other warforged to stay alive, but the bodies slowly "burn out", so they need a steady supply. They can possess regular golems instead of Warforged, but they burn through the bodies more quickly.
The possession process Edit
A Dark Ancient has to take the first level in the Dark Ancient Prestige class to be able to do their signature possession. The prerequisites are a bit unclear but you definitely need either arcane casting or psionic power manifestation. The exact requirements are still unknown, but must be pretty steep, because a warforged does change radically after taking the first level of the prestige class.
The mind of the warforged disconnects from their initial body and the mental energy being makes up the new warforged, in this form they are clinically immortal but they still have to be in a constructed body, so either a Construct or a living Construct, like another warforged.
To take another body they use their signature "Mind Transfer" ability that let's the Target make a will save (true constructs are not immune to that) and totally destroy their mind (or their operating system when they target constructs) and implant their own mind into their new body. The will save is pretty hard, but intelligent creatures get a +5 for that, though the dark Ancients have invented a tool, that gets them more bonuses when they can put this tool on a Construct.
They can always insert themselves into a body that they already occupied, or a special "possess me" kind of construct, especially made for the Dark Ancient.
Mechanical changes Edit
Should we include this?