Well of Souls

The Well of Souls, also known as the Mountian of Malefor, is a underworld in which spirits come to rest. If a weak or unprepared spirit were to enter, they will be possessed by another spirit and start reliving their past events though them. It become very difficult to break this hold over someone even when they're far away and needs considerable treatment to revert them.

It is said that Malefor created it with the help of the Convexity Element as a manner of training his soldiers through past experience. Since the collapse of the mountian however, the Well of Souls would never be used again.