Emissary Escort

A wall with a hidden attack step, priced for two mana and reliant on top-end you have not yet cast. The 0/4 body holds the ground the moment it lands; the power bonus keys off the single greatest mana value among your other artifacts, not the sum of them, and that scaling choice is the entire point of the design. A swarm of cheap artifacts does nothing for its offense. One expensive artifact does everything: resolve an eight- or ten-drop colossus and this becomes a real attacker for the cost of leaving up a counterspell, still carrying the four toughness that let it survive the ground stall it was built to sit in. The zero base power is the honest half of the bargain. With no big artifact in play it contributes nothing on the swing-back and simply blocks, so the payoff has to be assembled rather than handed over. That places it among the defensive bodies that convert into finishers once the rest of the deck comes online, closer to a mana-value-matters engine piece than a beater. Robot Soldier is the flavor wrapper; the mechanical identity is a cheap blue blocker that reads its own artifact top-end and turns the biggest number it can find into combat pressure.