Seal of the Guildpact

Five mana for a rock that changes nothing on the turn it resolves, sold on the promise that it earns back that investment later: that gap is the whole design. Each spell sheds one generic mana for every chosen color it carries, so a gold spell in your two declared colors comes down two cheaper, a monocolored spell in those colors saves one, and an off-color spell saves nothing. The reduction only ever touches generic mana, never the colored pips, so it accelerates a curve rather than fixing it. Cost reducers that name colors run back to early tinkering with affinity-for-color discounts, but the structural ancestor here is the locket-style reduction generalized into a static, always-on tax break printed on an artifact body. The catch is the front-loaded price: the discount has to claw back that five before it earns, which only happens in a grindy, spell-dense game where you cast multiple two-color spells per turn. Outside that exact shape it is slow and inert, an idle turn followed by marginal savings. The two colors are chosen on entry and locked, so there is no hedging once it resolves; you commit to a two-color identity and the card pays you for a commitment you have already made. The two-color deck most disciplined about its curve, the one that would extract the most from the discount, is also the one that least needs it.