Lord Xander, the Collector 
Legendary Creature — Vampire Demon Noble
When Lord Xander enters, target opponent discards half the cards in their hand, rounded down. Whenever Lord Xander attacks, defending player mills half their library, rounded down. When Lord Xander dies, target opponent sacrifices half the nonland permanents they control of their choice, rounded down.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL