Making the Scythian cool with bone razors...

I have a basic idea of what the history of the the Scythians are, but the biggest issue for me so far is creating their bone like blades.  So this is what I came up with:

Bone Razor (Ex): A Scythian can learn to create and manipulate their bones to create a sharp bladed object that can be used as a weapon. A Bone Razor is created from any bone spurt that might be covering the body of a Scythian. A bone razor once drawn is not attached or connected to the Scythian’s body. A Bone Razor can be used by others other than the Scythian that created it but it is considered simple weapon. A bone razor causes 1d4 points of piercing or slashing damage, plus any applicable modifiers. The critical threat modifier and critical multiplier for this weapon is that of a dagger (19-20/x2). A bone razor is considered to be a dagger and gains all advantages provided by feats affecting a dagger such as Weapon Focus (dagger) or Weapon Finesse. Abilities, spells, feats, and items that affect natural weapons affect a bone razor. A bone razor can be disarmed and sundered with a hardness of 10 and hit points of 2. A Scythian may keep the bone razor for a maximum number of rounds equaling to 5 + his class level. Once this time has elapsed, the bone razor will deteriorate to dust or may be merged back into the Scythian’s body that created it. Producing a bone razor is a free action, but a Scythian may only produce one each round. If attacked by their own bone razor the Scythian suffers no damage an the bone razor naturally merges back into their body.

Those is a rough draft of course, but the basics of the mechanic is based off of a mechanic we created for the P'Tan and have modified them to work for the Scythians.  Not so powerful, but interesting enough.  So tell us what you think or better yet tell us what we have done wrong. I can't wait to see the artwork.