Perpetual

A Perpetual is a being or object of great power that only exists in a single instance across all timelines, as opposed to everything else, which has a different, separate rendition that exists in each timeline.
It is not known the cause for a Perpetual's existence in every case, only that they are incredibly rare. Notably, the Font of Balance (previously the Font of Destiny and the Font of Consciousness before that) was used at an unknown time before the Cataclysm to transform the majority of the precursors into gods, with the Eight becoming the Lords. The Font was and remains a Perpetual, and the Eight Lords were also shown to be Perpetuals before their doom.
The list of currently known Perpetuals include:
* Erven the Eternal
* Asparan (suspected, if even still alive)
* The Font of Balance
* The Ingrain