Fractal Tender
The keyword this Elf Wizard carries builds a rising threshold into itself: the counter trigger fires only when a spell's mana exceeds the creature's power or toughness at that moment, so every counter it earns lifts the bar for the next. A 3/3 wants a four-mana cast to grow; once it swells to a 4/4, you need five, and so on up the curve. That self-limiting climb is what shapes deckbuilding toward the expensive end, where each big spell is likelier to clear the wall it just raised. The end-step payoff is where the mechanic pays out: land any counter during a turn and you spawn a Fractal that arrives as a 3/3, effectively minting a copy of the body's opening size off a single costly cast, no attack required. The design rewards a spell-dense midrange shell that reliably deploys something pricey each turn, not a tempo deck chaining cheap spells, since a fistful of one- and two-drops leaves the trigger asleep. Ward is the tax insulating the investment; a body meant to snowball over several turns needs cover from the cheap removal that would otherwise reset it before it returns value. Its ceiling scales with how expensive your spells get, not how many you can string together.
