It's usually important for aggressive decks to have lands that can be used the turn they come into play, but with so few dual lands, A-Raiyuu is in danger of the dreaded mana screw
The rare is a 5-drop 4/2 that will force a targeted foe to sacrifice a dork each time you become the monarch, and since it makes you the monarch first, that will be at least once
When he comes into play, pay two generic and then X, with X becoming the number feather counters that Kangee comes into play
With the tools to prune your own card, and a huge variety of effects that benefit from cards leaving your yard, I think Sin has the capability to really shine in lower-powered environments, given the permanence of its effect and high mana value
There are 5 rare monocolor Adventure lands in Magic: The GatheringFINAL FANTASY, and each has a borderless version
Sisterhood of Karn Sisterhood of Karn is a 1/1 that grows quickly into a 2/2, 4/4, or 8/8 with minimal effort, provided that it lives