These items have a name, it's
Shuriken (Japanese for "Secret Sword"). Forgive me, but even if it's deliberate, "ninjatsu" is simultaneously misleading, inaccurate, and...well, lame.
Mechanically, however, they seem on point. 3 Other for a weapon that deals 5.2 damage per round unupped seems about right. 3 Other for a weapon that does 9.45 damage per round upped also seems reasonable. Do they keep the skill when Animated? Because if they do, things like Chaos Power could get pretty brutal on them.