Now that 8.3 is out and we have been able to experience the Allied Races DK starting zone, during those events you notice that the Lich King is still encased in ice on the frozen throne. While browsing YouTube, I rewatched the Shadowlands Cinematic and noticed he was free from the ice and was waiting for her to appear.
I wasn't sure if this has been explained anywhere, but I wonder who ended up releasing him. Did he keep himself frozen and released himself when he started to expect Sylvanas to make her move, or did someone have to release him? I also wonder if we will be able to experience any of this in game, or will pre-patch just start with the undead attacking and we find Bolvar dethroned towards the end?
Would be a great quest for a DK character. Maybe head to Northrend, help Bolvar unfreeze, and maybe even be part of the group of undead that try to stop Sylvanas in the cinematic (she steps in, cinematic plays, etc). Then when it's over you talk to Bolvar with the broken sky above you and he tells you to get to your faction leader as soon as you can to tell them about the undead being uncontrolled.