For Ninja, your character should be:
all attributes >=17(for #1 to #4)
luck>=16 (for #5,6)
and, you cannot change NINJA with THIVES SWORD. (You can change NINJA with THIVES KNIFE in #1,2.)
a BUTTERFLY KNIFE can change to NINJA. **CAUTION NEVER USE TWICE**
> One more question. I cannot get Ninja. Character is Chatoic, above 15 in all stats. (Hobbit thief) Even Thieves Sword does not change to ninja!
> Created a second thief (human), but thieves sword still does not change to ninja.
> Playing on IPhone XS, iOS 12.2. A bug?