Denkibou's metal claws
Essentially it's another ninja weapon (Iga ninja, to be exact) called a tekko-kagi. Worn on the back of the hand, just as this set is. However, I do not know that tekko-kagi were ever made with folding claws like these; the only examples I can find images of look to have been cast in a single piece. So I'll tentatively say these are probably anachronistic; they're based on something of the time, but their technology may be too extreme for the Edo Period.