Ioreth of the Healing House

The second ability is the whole reason this Cleric exists: untapping two other legendary creatures at once is a payoff that scales directly with how many legends you can cram into a single board, and does effectively nothing in a deck that runs one or two. That is an unusually steep power curve for a three-mana untapper, and it tracks entirely with density. Read strictly, the first ability is a general-purpose untapper for any single permanent (a land, a mana rock, an artifact), which is a small but real thing in Blue given how much of the color's untap work historically pointed at specific card types. The second ability reframes what a legendary creature's tap ability costs: any legend that pays with its tap symbol becomes a resource you can fire twice per turn cycle, and doubling that across two of them at once is where the ceiling lives. The 1/4 body is built to sit still and enable rather than attack, with four toughness dodging enough incidental removal to keep the engine online. What gates the whole thing is Ioreth's own tap cost: she untaps one pair per turn on her own, so the output is capped by how many additional untap effects you can chain rather than by raw repetition. A targeted enabler wearing the frame of a modest support creature, valuable in exact proportion to the legendary company it keeps.