The Tentacled One
While I could easily build a deck to take massive advantage of the plane, the precon really doesn't have very many slots that can make use of it. Checking the decklist, I'm seeing Beacon of Unrest (one copy), Dregscape Zombie (one copy), Gravedigger (one copy), Rotting Rats (one copy), Soulless One (one copy), Cruel Revival (one copy), and Profane Command (one copy). So that's 7 slots out of 60. Of those 7, 1 cares about cards in your opponents' graveyards, 2 can be used from your graveyard, and 4 can be used to get creatures back from your graveyard. That's better than what anyone else at the table gets. The plane is certainly worse for the rest of us than it is for you. But you're not exactly "yes, please mill me" territory, in my view. Also, I think most of your other planes do more for you.