As far as being unique amongst the Unmade go, uniqueness isn't black and white, it's a range. Every person is unique, but some are more unusual to others.
I don't believe we know of another Unmade that can corrupt other splinters, do we? The rest either cause cognitive influence of some kind, bond people to grant power (Yelig-nar), or simply don't appear to interact with other individuals directly at all (Re-Shephir).