Lord Xander, the Collector
Legendary Creature — Vampire Demon Noble
Oracle Text
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.
Watch Out
This card's ability triggers when it enters the battlefield, not when it's cast. Effects that double ETB triggers (like Panharmonicon) work here. Countering the spell prevents the creature from entering, so the ETB won't fire.
'Dies' means 'put into a graveyard from the battlefield.' If a creature is exiled instead of dying (Swords to Plowshares, Rest in Peace), dies triggers won't fire. Tokens do trigger 'dies' abilities briefly before ceasing to exist.