Knight-Errant of Eos

Convoke is what turns this from a durdly five-drop into a payoff for going wide, and the design couples the discount to the reward. The number of creatures you tap to cast it becomes the mana-value ceiling on the two cards you dig up, so a token-heavy board doesn't just make the Knight cheaper; it also raises how expensive a creature you can rebuy from the top six. Every creature you tap adds one to that ceiling regardless of its own size, so the deck that wants the biggest search is the deck flooding the board with bodies: tap a swarm of one-drops for the discount and X climbs high enough to pull two of your best midrange threats back into hand. That coupling is the whole trick. The resource you spend to deploy it is the same resource that scales its reward, and a 4/4 body that refills your hand twice over is generous card advantage for a white aggressive shell, which has historically had to fight harder than the other colors to recover from an empty grip. It answers the old problem of the go-wide deck running out of gas after the alpha strike, and it does so without breaking the sorcery-speed, enters-the-battlefield discipline that keeps it from becoming an instant-speed engine. It rewards a board you already wanted to build, then hands you the next two turns of pressure.