Underrealm Lich

Every draw becomes a dig: look at three, keep one, and feed the graveyard the other two. That single substitution rewires two axes of a deck at once, because the yard it fills is not an incidental byproduct but the second half of the engine. Each card you draw stocks the graveyard two cards deep, so delve, escape, reanimation, and flashback all fill as fast as your hand does. The redirection is not optional and not once per turn: extra draws from other sources also become forced top-three digs, which is the real subtlety of the design. Because the replacement swaps the draw entirely for a look-and-mill, you cannot deck yourself out while this is on the battlefield; the empty-library loss trigger simply never fires, and instead the library becomes fuel to be spent freely. The more card advantage you generate, the deeper you carve into your own deck, which pushes toward treating the graveyard, not the hand, as the actual resource pool. The self-protection clause keeps the body around long enough for any of that to matter: four life for indestructible is a steep toll, but it beats nearly every removal spell that does not exile, and because the ability taps the creature, you spend it as a defensive reflex rather than a way to force damage through. The 4/3 frame is almost beside the point; what this card is doing lives entirely in the rules of drawing, not in combat.