Hmm I'm wondering at the intent behind the Ninja-to strike is. Is it to encourage people to do call stuff in combat? It would appear so, but it is too easy to just say "I jump two squares then charge the guy" when there is no reason to jump and no cool cinematics to it.
It seems to be designed to encourage jumping off things onto people or jumping at people. I guess that is hard to make rules for, and it is not overpowered even if it can be used every turn.
I might houserule that the attack can do an extra Dex damage if used for something really cool, like jumping off a house onto someone etc. Or that it lets you use flight, jumps etc as part of a charge more easily.
I really like the shuriken ability. Even without the poison thing, I just love attacks that hit multiple people, I think that damage could really add up at high levels. At low levels it is pretty much just a minion popper without the poisons though.
