This is a replica of the Brides' sword Kojiri (scabbard end cap) from the Kill Bill movies. It's sized to fit a typical Chinese-made saya, which are generally more chunky that Japanese-made Iaito saya. No guarantees on the fit, though:)
This design was originally made by a guy that goes by the name “Haotian Niu”, but I've lost touch with him over the years. We collaborated on designing this kojiri, but he did most of the heavy lifting.
I recommend that you print this on a resin printer for maximal detail. Or, if you want, I've got it posted up on shapeways if you want a metal version (or a high detail plastic one).
http://shpws.me/TaRo
The author hasn't provided the model origin yet.