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.
Lord Xander grinds opponents out through forced discard, mill, and sacrifice triggers, each firing at a different point in his life cycle. You want to leverage all three abilities by reanimating, blinking, and sacrificing him repeatedly while controlling the board. The deck wins through attrition and value, often closing with a big swing or a mill-based finisher.
Three powerful disruptive triggers that hit hand, library, and battlefield
Grixis colors give access to the best removal, card draw, and tutors
Excellent payoff for reanimation and recursion engines since each cast/death is value
Strong against control and combo decks by stripping hands and permanents
Seven mana for a creature that does nothing the turn it lands unless protected
Triggers only hit one opponent at a time, slow in a four-player pod
No evasion or built-in protection, easy to chump or remove before value
Vulnerable to graveyard hate that shuts down reanimation lines
Turns Xander's mill into massive incremental life loss, converting the attack trigger into a real clock.
Add fast mana like Mana Crypt, Dark Ritual, and Jeska's Will to deploy Xander ahead of curve, plus reanimation tutors like Entomb and Buried Alive to set up cheap returns. Include blink and flicker effects such as Conjurer's Closet or sacrifice loops with Feldon to re-fire triggers every turn. Finally, tighten removal and counterspells to protect Xander and reach a more competitive control-attrition shell.