Takenuma, Abandoned Mire

The whole appeal of this cycle is that the card asks nothing of your deck to earn a slot: it is a black source that never costs you a land drop, but one you never have to play as a land at all. That is the tension it resolves. A tapland-quality Regrowth effect stapled to a Swamp would be a nonstarter; a card that can be a black source or a Regrowth, chosen the moment you draw it, is close to free. The Channel decision lives entirely in your hand: you keep it to make mana or you pitch it for the recursion, never both, so the whole cost is the flexibility of one card slot. It is not a strictly better Swamp only because it enters as a legendary nonbasic, which limits it to one copy in play and leaves it exposed where basics are not. The mill three attached to the return is not filler: it feeds the graveyard the same ability digs through, so the effect can supply its own targets even from an empty yard. What pushes it past a fair rate is the legend-count discount, which rewards decks already stacking legendary creatures and can shrink the activation toward a single black mana on a developed board. Recovering a creature or planeswalker at instant speed is the kind of low-friction value fair midrange has always paid a premium for; here the premium is a card and a bit of black.