Phase Out refers to the ability possessed by the Keepers of Abassid allowing them to disappear using an unnamed device and reappear with almost all damage recovered.
Overview[]
The exact details of how the Phase Out system works is unclear, however it does seem to be based around a device built inside the Keeper that charges up and allows them to disappear to another location to recover damage taken. This system seems to be triggered when a Keeper drops to a specified damage level, half of their total hit points to be more precise.
This ability appears to be used only by the Keepers of Abassid as no other Keeper was shown accomplishing such a feat.