Library

Fixing blue and red on the same tapland already tells you which guild this belongs to: Izzet is the color pair that treats card selection as a resource, so a mana source that can also spend surplus mana to Investigate lands exactly where that identity lives. The Investigate line is priced to stay out of your way: four mana to make the Clue, then two more to crack it, six mana in total before you see a card. That expense is the entire point of putting a repeatable card-advantage ability on a land. It enters tapped and asks a steep toll so it never warps your early curve or tempo; it exists to convert a flooded board into cards once the rest of your hand has run out. Investigate on a land is scarcer than Investigate on a spell or creature, because a land that also draws cards drifts toward the kind of self-sufficient utility land that historically proves very hard to answer. The gating keeps the design honest without gutting it: you pay full retail for every Clue, and the mana it consumes is mana you were unlikely to spend elsewhere. What you get is a fixing land that quietly turns the late game's dead draws into fuel.