When Splinter enters, destroy up to one target tapped creature.
When Splinter leaves the battlefield, you and another target player each draw a card.
Splinter is a mono-white blink/recursion engine: every time it enters, it kills a tapped creature, and every time it leaves, you draw a card. The deck loops Splinter with flicker effects and sacrifice outlets to grind out removal and card advantage, while building a wide or tall board to close the game. You want enablers to tap down enemy creatures so the ETB always has a target.
Repeatable creature removal stapled to your commander, which mono-white badly needs
Built-in card draw on every departure helps offset white's notorious card disadvantage
Cheap 3-mana body that rebuilds value through blink and bounce loops
Politically friendly leave trigger (draws for an ally) can buy goodwill or seal deals
Removal only hits tapped creatures, so untapped threats and many problem permanents dodge it
Mono-white's classic shortfalls: weak ramp, limited card draw outside the commander, no interaction with the stack
Relies on flicker/blink pieces to generate value—without them Splinter is just a vanilla 3-drop
Vindicate-style targeted removal and graveyard hate can disrupt the loop engine