Currently, the only known creators of such inter-dimensional portals are the descended energy beings known as the [[Brownshirt]]s. Other entities also appear to be able to traverse parallel universes, such as [[Sentient Flame]]s. The [[Regret Demon]] is capable of hijacking an active portal and redirecting its destination to a location of its choice.
Portals can also be generated by the [[Portal hub facility]]s, which seem to be capable of targeted inter-dimensional travel.