This weapon is called "Kogake". It's a Sparring type melee weapon in the game. They're pairs of knuckles (both for the hands and feet). "These coverings for the hands and feet allow devastating high flying hand-to-hand combat attacks without risking harm to the user."

This Kogake is only an MR fodder weapon for me, since I'm just gonna rank it up to 30 then use it to make "Hirudo" (another sparring-type weapon). If ever I'll be keeping one, it would be the Kogake Prime.