Mannequin is art and inspiration that controls the artist. It whispers sweet things to the artist, promises her fame and recognition etc, while simultaneously saying that she is worth nothing and a failure. That way, it manipulates her. It comes from the Toymaker, as a creation of him, or his former Name. The Mannequin is obsession and search for perfection that one thinks is reachable, but of course does not exist. It has a spindle and thread that the Modiste follows and she thinks that it will lead her to greatness/inspiration, but it actually leads to the Mannequin and is its ploy to lead her astray and make her always come back for more.
The Toymaker wanted a friend, as his Names mostly work, and the Marionette is just a bodyguard. He made himself the Mannequin, with a purpose to be loved, but that aspect got out of hand. It started desiring and craving everyone's obsessive love for itself.
God-from-Craft, since it was created by the Toymaker.