During the pre-launch event for World of Warcraft: Shadowlands, Bolvar
had an important role. Sylvanas confronted and defeated the Lich King
and then shattered the Helm of Domination, effectively setting up all
the events for the main expansion. Not long after, Bolvar (and players)
go to the Shadowlands to try to stop Sylvanas.
After venturing to the realms of the afterlife, players are first
introduced to the Maw, a location that serves as World of Warcraft:
Shadowlands' endgame. Although events cause players to leave the Maw
upon first arriving in Shadowlands, they'll eventually be brought back
to the zone by the expansion's end. Famously, Arthas Menethil was cast
into the Maw after his death as the Lich King over a decade ago. Because
of this, fans speculated that Arthas could be in the new WoW:
Shadowlands expansion.
The Maw primarily serves as Shadowlands' endgame content, so it makes
sense that WoW's Arthas Menethil will be there. Most of this will likely
relate to Sylvanas, since she was killed by Arthas in Warcraft 3 before
Arthas resurrected her. Since Sylvanas is such a major character in
WoW: Shadowlands, with such a storied history with Arthas, then it makes
sense he'll show up at some point.
Close to the beginning of the endgame content for Shadowlands, Sylvanas
reveals her plans to change the way the afterlife works. While her
reasoning isn't completely explained (Sylvanas is still Sylvanas, after
all), it certainly opens the door for players and Sylvanas to meet World
of Warcraft's Arthas Menethil again. It's reasonable to assume Arthas
will appear at some point in Shadowlands, even if it's in a future
update after launch.
An iconic character like Arthas Menethil will surely appear in the
expansion at some point. He's already been sent to the Maw, so it makes
sense that players would run into him there. However, it may be that his
appearance is being saved for after the initial events of the game,
since that would be a huge reveal. If Arthas isn't in World of Warcraft:
Shadowlands, it will be a major missed opportunity. Chances are good,
though, that he'll finally show up at some point.