Darksteel Forge

Indestructibility was Darksteel's signature: the set introduced Darksteel Ingot, Darksteel Citadel, and a clutch of permanents stamped with the keyword individually. This is the engine that universalizes it. Where Darksteel Colossus protects only itself, the Forge throws the blanket over the whole board: every artifact you control, present and future, shrugs off destruction-based removal as long as it sits in play. The keyword's wording is the load-bearing part. Indestructible answers "destroy" effects and lethal damage, and nothing else, which is exactly why the Forge does not break the game it sits in. It does nothing against exile, against -X/-X, against bounce, against sacrifice clauses, against losing the game outright. An opponent who reaches for Vindicate gets stonewalled; one who reaches for a sacrifice edict walks right through. At nine mana with no immediate impact on the board, the card is the definition of a payoff: it asks you to have built an artifact deck dense enough that a mass indestructibility shroud actually matters, and to survive long enough to untap with it. That positioning has made it less a Constructed staple than an artifact-tribal capstone, the card you ramp toward in a deck where every other permanent is metal. The design lesson it taught was durable: a keyword that only stops one category of removal can headline a set without warping it, because the answers it leaves open are the ones that matter most.