Runecaster of the Nexus

When Runecaster of the Nexus enters the battlefield, exile all instants and sorceries from each player's graveyard.
At the beginning of each player's upkeep, you may cast an instant or sorcery card from any player's exile without paying its mana cost. If that spell would be sent to the graveyard this turn, shuffle it into its owner's library instead.
Intelligence, mystery, with a hint of madness.