Nikya of the Old Ways
The mana-doubling half is the sales pitch, and it is a good one: every land you tap pays double, and the restriction that buys it is the harshest tax Gruul has ever handed to a ramp piece. Locking off noncreature spells does not just gate an engine; it dictates the whole deck. No signets, no removal spells, no board wipes, no counter-magic, no sorcery-speed ramp: the doubler is worth building around only if everything else you play is a creature. That constraint is the entire design argument. Rather than gate the payoff behind a life cost or a tap-out, the card gates it behind deck identity, forcing a build that is all bodies and asking whether pure creature-based Gruul can generate enough raw mana to outrun decks that get to run interaction. The doubling reads like Mana Reflection stapled to a 5/5, but Mana Reflection asks nothing of your other card slots; here the payoff and the prohibition ride the same permanent, so you cannot bank the mana this turn and answer a threat the next. Few creatures in the color pair make the text on the battlefield matter less than the text they impose at the deckbuilding stage: you commit to the restriction before the game starts, and this 5/5 simply enforces the bargain once she lands.
