More or less a Blue Ninja deck, with some Red thrown in for the Haste/Unblockable effects.
The point of this deck is to get creatures through as reliably as possible to Ninjustu in your (probably stronger) Ninjas, and then in general to continue punching holes in your opponent's defense with unblockable damage - while maintaining control of their creatures with Sleep, Frozen Solid, Sunken Hope, and Mistblade Shinobi so they don't have the opportunity to counterattack. This is a pretty fast, aggressive deck that has worked well for me among my friends (we play pretty casually though, so it could use more rigorous testing and feedback - also why I don't have a sideboard).
As far as the Maybeboard, Spire Golems are a highly respectable flyer that, later in the game, will end up costing you 0 Mana most of the time. Incite Hysteria is a much more potent version of Nightbird's Clutches against Monocolored decks or even Multicolored decks whose creatures all share a color, albeit without Flashback. Shuriken is a great equipment for any Ninja deck, and Ronin Warclub is extremely potent in any Ninja deck as well thanks to Ninjutsu. In this deck in particular, with Fervor and Triton Shorestalker, the Warclub can help you consistently hit your opponents even with no Ninjas available. Pendrell Mists can help you keep your opponents' fields clear, especially against decks that pump a lot of creatures out that would otherwise overrun your Ninjas.
Notable Combos:
Despite having a lot of synergy overall in the deck, there are not many designed hard combos. However, there are a few combos that do work well.
Fervor
+
Sunken Hope
- your Fervor, combined with low cost creatures and Ninjutsu, will give you a strong advantage over your opponents when everyone loses a creature every turn automatically. Consider adding one or two more Sunken Hopes for even more powerful removal.
Fervor
+
Triton Shorestalker
- with Fervor on the field, the Shorestalker is a guaranteed 1 damage (3 if you run Ronin Warclub) at the least, or a guaranteed Ninjutsu target for U every turn that doesn't have to wait out summoning sickness. Combined with Mistblade Shinobi, this combo is UU for 1 damage and an Unsummon. With Ninja of the Deep Hours, it's 1UU for 2 damage and a card draw. With the other Ninjas, it can be 1UU to look at the opponent's hand (+1 damage) or 2UUU to pull another Ninja (+3 damage).
Higure, the Still Wind
+
Whispersilk Cloak
- putting the Cloak on Higure makes farming Ninjas from your deck safe and easy, and protects Higure from all but board wipes and being used as a sacrificial blocker so he can consistently send your other Ninjas straight to the opponent's health.
