A 'ninja' type?
To be honest I would not reccomend using unarmed as an offensive tool... It just doesn't work.
However, if you were going to create a character and call it a ninja, there are a few skills i would associate with them:
Poison arrows (does what it says on the tin)
Blind (again, does what it says on the tin)
Hide in shadows (allows you to become invisible for a short period of time)
Rush attack ( allows you to close great distances in the blink of an eye, and do great damage)
Fatality (instant kills)
Thousand strikes (very powerful and quick melee attack)
Ranger stealth (alows you to get closer before being spotted)
Evade (a chance to evade attacks)
I would also give him/her a two handed sword or dual wield weapons...ninjas don't use shields, maces or hammers in my mind!
These are skills i would associate with ninjas, but as far as building a character around them... well i'm just not sure.
Anyway good luck, and i hope you enjoy the game as much as i have
Tinman21