This is just awful, and the art sucks too.
She's build-around in that you need enough tribal support for her ability to be relevant, and you need ways to protect her long enough to use her. And you need to protect her in combat.
This one will take some playtesting to determite her true strenghts and weaknesses.
The good news is, it's White, so it automatically goes into any deck along side Academy Rector.
I'm already thinking Vish Kal is going to make a better general than I initially thought... Vish Kal, Academy Rector, Grave Pact and Martyr's Bond... oh boy!
Anyway, Riku has the potential to be the most degenerate of all the new Legends. Just imaging copying a Time Stretch and you'll have some idea of the hijinks Riku can get up to.
But just how broken Riku really is depends on what else is in your deck. Copying a Mulldrifter or a Prophetic Bolt is one thing, but copying Warp World or Genesis Wave could be game-ending.
For the most part, though, I think killing Riku on sight will usually be the smart play.
Zur. Birthing Pod. Demonic Tutor. Scion of the Ur-Dragon. Captain Sisay. Eye of Ugin.
Mana ramp. MANA RAMP!
Skyshroud Claim? F U.
Syphon flesh is not as good as either of those cards. But it is good. In any deck with a Zombie tribal theme, it's going to be fucking amazing. Anywhere else, it's just okay.
If it was 4 mana, I'd probably play it everywhere.
Saavy players will only fall for her once, if at all, but here's the thing... you only need to get one player on your side, and start giving that player stuff to beat down on your other opponents. Then the player(s) who know what your up to might want to stop you, but they have to choose between killing you or the opponent you are helping out the most.
If they try to kill you, the probably leave themselves open to attack from that player.
The thing I'm worried about here is "king-making", where one player basically hands another player the win. That's annoying. But Zedruu and her deck look like they are capable of playing to win, rather than just handing someone else game after game.