Any other good ninja movies out there? Or have I seen them all already?
If you don't mind Japanese ones, no masks, and non-modern setting, there are two :
The first is
Shinobi : Heart Under Bladehttps://www.youtube.com/watch?v=KI7YVeFf3HoIt's more battle of Ninja clan though, not a story about single Ninja fulfilling his mission.
They use every tricks necessary to make their clan is the best one.
The second is :
AzumiThe story began with several students whose trained to be Ninja.
Later they learned the hard way that their job later was not just regular "Spying" ninja, but as "Assassins" Ninja.
It has a sequel (Azumi 2) but not as good as the first one.