Templar Knight

The activated ability is why this card breaks from the "any number" convention that otherwise belongs to basic lands, Relentless Rats, and a small club of splashy singleton-defiers. Tapping five untapped attacking creatures all named Templar Knight is a build restriction disguised as a payoff: the toll is a swarm of the same 3/1, and the reward is a legendary artifact dropped straight onto the battlefield without paying its cost. That structure asks you to commit a whole board to a single name, then convert combat presence into a tutor, which is a different economy from most creature-based tutoring. The requirement that the five be attacking (not merely tapped) is the sharpest constraint: you cannot assemble the toll at instant speed on a clear board, so the ability lives inside your combat step and exposes the whole squad to blocks and removal on the turn you want to fire it. This is exactly where vigilance does its quiet work: an attacking creature would normally be tapped by the act of attacking, but vigilance keeps these bodies untapped as they attack, which is the only way to have five untapped attacking creatures available to pay the cost in the same combat step. The 3/1 body reads as pure enabler, glassy enough to die to nearly anything but cheap enough to flood the board with copies. It is a tribal engine that names itself, a rare case of a card whose deckbuilding thesis is printed in its own activation line.