I’ve never played Nioh, but I wanted a mechanic where the player is encouraged to save their consumables for when they really need them but not to the point where they start to just hoard them for the entire game. My main inspiration was actually the sub tanks in the Mega Man X games with how they can be re-filled as many times as you want, but I wanted a system that ties in more closely with the exploration aspects of the game.
Too bad Frodo never knew about that.