Eiganjo Castle

Most utility lands of this era leaned on a life payment to bend a color or a rate; this one taps for white cleanly and stacks its second ability on top of a real mana source, so the prevention is upside rather than a tax. The damage prevention is the reason its legendary restriction earns its keep. Two damage stopped before it reaches a legend reads like a flavor concession until you map what it actually answers: a point of burn pointed at your most important creature, a 2-power attacker swinging through, a combat trade where one extra point of toughness flips the math. All of those tilt the other way for a single white and a tap. It heads a cycle of legendary lands built on the same bargain (a free tap for mana, a costlier ability that rewards leaning into legends), and among them it is the one that touches combat rather than cards or tempo. The prevention is reactive, available at instant speed once a spell is on the stack or an attacker declared, which distinguishes it from the proactive lands it otherwise resembles. The quiet job is keeping your single most important creature alive across the turns that decide a game.