All games need items, or at the very least props to interact with. Most of these are just props. I wouldn’t like to burden the game with an inventory, collecting mechanics and shop system, so I’ll just make it straightforward interaction-wise.
You use this Shinto Exorcising Wand and send demons back to hell. You have it already equipped. Traditionally, it’s supposed to have two or three strands of paper, or so English sources assure me. I found, however, many examples with multiple layers of strands, so I just went with whatever seemed nicer and ominous (FOUR strands, BWAHAHAHA!). I chose an archaic nomenclature for it because, c’mon, it’s an Edo drama set in Edo Japan, amirite?
You’re supposed to collect these. They will all feature the boss that has corrupted them. After the boss has been exorcised, the motif will change to reveal a nicer aesthetic. They’re so simple, it seems like a joke to put them at the very center of the plot.
These will just be a fancy save-regenerate station. You find a shelf altar and use the spirit bells (already included with your garden-variety shinto maiden) to dance around, invoke the gods and heal yourself/save the game.
Aaand… that’s it! I may make mini-games where you’d have to collect some stuff around the house, but I would make a counter on the HUD instead of an inventory item where you’d have to pause to check every time your short-term memory craps on you.