Amber Prison

The Amber Prison is an artifact in which Kaervek locked away Mangara and hid him in the Mwonvuli Jungle. After Scalebane's Elite and Asmira set Mangara free, Kaervek himself was locked in the Prison.

It is possible that the amber prison, located in the prison-city of Aku was removed from the timeline by Teferi along with the rest of Zhalfir.