Urza, Lord Protector

Meld is the game's most expensive design conceit: two cards that combine into a third, which means both halves have to justify their slots independently before the payoff ever arrives, and the payoff has to be worth assembling a two-card puzzle across a full deck. This half solves that problem the only way a meld piece honestly can, by being a card you'd run without ever caring about the back half. A cost reducer on artifacts, instants, and sorceries is a broad, always-relevant discount that anchors any spell-dense build, and the 2/4 body survives the early turns rather than dying to the first ping. The meld ability is deliberately buried behind a seven-mana activation and a sorcery-speed clause, so the transformation reads as a reward for a game that has already gone long, not a combo you're racing toward on curve. What separates this from most meld designs is that the reduction stands entirely on its own; the second component, the artifact The Mightstone and Weakstone, likewise functions as pure ramp without its partner. Two independently playable cards that happen to fold into a planeswalker: that is meld working as intended, rather than the usual trap of two dead halves waiting on each other. The fiction of an artificer and his rival's twin stone becoming a single walker is carried by cards that don't need the fiction to earn their place.