We've datamined some voice lines between the Primus and Bolvar which may indicate what happens at the end of Shadowlands. Major spoilers ahead.
SPOILERS!!! Possible Major Story Spoilers Ahead. The Fate of the JailerFrom the 9.2 PTR, we've datamined some voice lines from the Primus and Bolvar. However, the exact context of these voice lines is unknown but at least one of the voice lines seems to make it clear as to the fate of the Jailer. The quote from the video is as follows.
The Jailer, Read more on wowhead.com