You gain the Special Weapon Proficiency feat with carbonedge shuriken (and no other model of shuriken) as a bonus feat. Additionally, you can add your Dexterity modifier rather than your Strength modifier to ranged attack rolls with carbonedge shuriken, and you make melee attack rolls with carbonedge shuriken as if they were basic melee operative weapons. You can use the trick attack class feature with a carbonedge shuriken. At 3rd level, you gain the Weapon Specialization feat with carbonedge shuriken (and no other model of shuriken) as a bonus feat. At 12th level, you deal an additional 1d4 damage with carbonedge shuriken and treat them as having the injection weapon special property. At 17th level, the additional damage dealt with carbonedge shuriken increases from 1d4 to 2d4.