Sounds like a really scary character. I remember liking the Mawkin. I'm all for it.
Edit: Now I remember thinking it was a tad weak, and looking it over I agree, up until the point where it gets Lurking Shadows. Allowing Extra Rage and Extend Rage (or homebrewed feat equivalents) to apply to its Mawkin/Nightmare forms would help. The # of uses and duration on those is kind of low. Also, if you could use Instantaneous Rage (or an equivalent) to use Mawkin/Nightmare forms with lesser actions (or maybe dip Factotum) it would also be a big help.