When we evaluate new cards for constructed, there are a couple of different roles that we look to fill. The most obvious is finding replacements for old staples when they rotate out (like Maro for Erhnam Djinn in G/W Armageddon) or improving a deck by replacing a card with a more efficient version of the same (like Shock replacing Kindle in Deadguy Red). Least common is a card, like Mind's Desire, that can serve as the cornerstone of a whole new deck; though when such a deck appears, yet another category opens up... the cards that are made constructed quality by such a deck, and usually only in that deck (say Task Force or Myr Enforcer). From my first blush, I would say that the Ninja fall mostly into the last two categories.
The most impressive of the group, and arguably the catalyst for a Ninja constructed deck, is Higure, the Still Wind.
Along classical parameters, Higure is a 3/4 creature for . One of the best creatures Morphling was a 3/3 creature for with five special abilities (all right, four and a half); Higure only has three abilities, but along with his greater base size one is card drawing, the most powerful mechanic, give or take, in all of Magic.
Among Higure's advantages in constructed is his ability to come in on four mana. A 3/4 creature for four mana is much more interesting than one for five. Using a quick evasion flyer (we'll get to that, specifically, later) to get Higure into play allows for at least a single devastating turn, hopefully turn three or four.
Now beyond Ninjutsu itself, two of Higure's abilities only work (or at least best work) in concert with other Ninja. His "Eladamri's Call" ability is like a turbo-charged version of the Ophidian ability, which, while potentially more powerful than the standard Ophidian ability, can't dig up your next land and also requires you to have a couple of relevant creatures in your deck to work out properly. Higure's evasion ability not only keeps him hitting -- and drawing more cards -- but can force through Higure’s minions as well.
Mistblade Shinobi is an interesting card only because of its low Ninjutsu cost. A 1/1 for three mana is pretty pathetic, especially when its ability requires it to actually connect with the opponent's jaw. Mistblade Shinobi will be most useful in a situation where you are coming in with a cheap drop against the opponent's early utility creature -- maybe a Birds of Paradise or Thought Courier... something that he isn't going to want to use to block -- and then set him behind a turn. It is also reasonable in the mid-game. Imagine a situation where you are already dominating with Higure so that you have several Ninja. You can try to swarm your opponent, or you can just use Higure's ability on Mistblade Shinobi to make sure your opponent can’t ever catch up. Perhaps most important given the constructed landscapes over several formats, Mistblade Shinobi can also undo the hard work of Arcbound Ravager.
Because of all this, I think that green may be a strong color to pair with the blue Ninja. For one thing, green has the best one drops. It might be odd for a Birds of Paradise to attack on turn two instead of accelerating something out, but when the reason is that Ninja of the Deep Hours is about to draw a card on its evading back, a Birds played that way is almost better than one actually playing a turn two Ophidian. In addition, green is currently the best color to take advantage of Ninjutsu's "drawback". Look at powerful “187” creatures like Eternal Witness and Viridian Shaman (187 is old constructed jargon for creatures that do something special when they come into play). They are good the first time around... why not give these green Grey Ogres another chance to shine?
Branching out into black, there are at least three interesting Ninja to talk about. Skullsnatcher is in a traditional sense the best of the black. His ability is fairly modest (unless you are playing against an Odyssey Block-based U/G deck or Reanimator variant), but Skullsnatcher is a 2/1 creature for , making it the only traditionally efficient hard cast of all Ninja.
Throat Slitter is a well-costed card. Essentially a Dark Banishing on wheels, its Ninjutsu cost matches perfectly. Like Mistblade Shinobi, Throat Slitter is going to be at its best on the first swing -- when the opponent has a dangerous creature that is at least temporarily unwilling or unable to block -- but can be even better than Buried Alive for Genesis and Bone Shredder come mid-game, especially if it was searched up by Higure, the Still Wind.
One thing to remember is that, besides maybe Ink-Eyes, Servant of Oni, the Ninja work best in aggressive decks that do a lot of early attacking… That many are blue – the least aggressive beatdown color in Magic – puts these creatures a bit at odds with their fundamental nature. Ninja tend to be inefficient creatures on their own, but can piggyback cheap evaders to very good effect. The Ninjutsu mechanic is one of the best reasons I've heard of to dust off those old Spiketail Hatchlings, and can give you an incentive to bring Nezumi Cutthroat over from limited-only service.
Now because the best Ninja will be filling your hand with cards, you will need mana to spend them all. We've already pointed out Birds of Paradise -- which in addition to helping you cast your Ninjutsu booty can help get your Ninja Tomes past potential blockers -- but another strong candidate has to be the mighty Aether Vial. While Aether Vial might not have an immediate synergy with Ninjutsu (itself a way of getting creatures into play without being properly cast), its overall synergy with the kinds of cards that work well with Ninja makes it a valuable source of mana acceleration.
Overall, I think that Ink-Eyes will be the most "independent" of the Ninja, working her way into decks as a strong finisher, while her blue peer Higure will only be played in Ninja-heavy decks. Ninja of the Deep Hours may be played without any of his teammates in a U/G or similar deck, more-or-less like the original Ophidian was; unlike Ophidian, Ninja of the Deep Hours will be more difficult to protect due to its small toughness.
The Ninjutsu mechanic has a lot of potential, but right now, I think its biggest drawback is speed. For the Ninja to be successful in the future, they will have to find a way to counterbalance their inherently clunky mana structure in order to race existing tuned decks. Our suggestions of swinging with Nezumi Cutthroat into third turn Throat Slitter or replaying 187 creatures via mana acceleration are two attempts to solve this problem.
Read The Week That Was Tomorrow. Trust me.
If you tuned into the Pro Tour Nagoya coverage this past weekend, you know that Brian David-Marshall did a great job filling in for me during the live Webcast of the Top 8. Tomorrow his column is going to pinch hit for Swimming With Sharks with a new feature that, once it gets going, is simply the most exciting content ever run by any website, for any constructed format, ever. Like I said, make sure you check out Brian's The Week That Was. You won’t be sorry.