It looks like a "theater" knife. As in, a knife someone made in a combat zone out of whatever was available, and using a shortened bayonet or or other issued blade. And as a result, the markings are gone (because they were on the end of the blade that was cut off to shorten it).
Or, it could have been made by some guy in his garage

.
Short of any markings, or other pictures on the internet providing provenance/history, or the identity of the maker, I doubt it will be possible to definitively identify the maker.
Still, it's a cool knife.