The Behemoth's Lair Q&A hinted towards something from the old universe, and now, the official site has announced the return of VARN for the special adventure pack called "Pirates of the Savage Sea":

"The map “A Princess of VARN”, contained in this Adventure Pack for Might & Magic Heroes VI, takes place shortly after the events of Legends of Might & Magic.
Penelope has been rescued from the Necromancers, but discovers things have taken a turn for the worse during her captivity. Her father, King Alamar, is dead, and his former vassals are now battling to conquer the throne. And the cabal of the Necromancers, which engineered the whole situation, is still up to no good.
Penelope will have to take arms to restore her kingdom and reclaim the Mandate of Heaven. Hopefully, she'll succeed in it..."