Kjeldoran Outpost

The cleanest expression of Alliances' obsession with land sacrifice as a resource cost. The entry replacement is the whole design: it never arrives free, it eats a Plains on the way in, and if you have no Plains to feed it, it never lands at all. That friction is what pays for the token engine. A land that taps for white and also manufactures 1/1 Soldiers indefinitely would be absurd at the rate of a single Plains; the sacrifice clause makes it cost two cards' worth of mana sources for one, so the deck that runs it accepts a permanently smaller manabase in exchange for a recurring, removal-resistant army that lives on a land slot. The Alliances "Outpost" cycle built every one of these lands the same way (each demands a sacrificed basic of its color and turns into a repeatable token or effect), but this is the member whose math people actually solved: in a build heavy enough on Plains to absorb the cost, an Outpost becomes a sink that converts flooded turns into bodies. It is an early answer to a problem every grindy white deck eventually faces, which is what to do with excess lands once the curve is spent. The idea of a land that produces creatures recurs constantly in later design, but it started by asking you to pay in basics first.