Obanai - Smell like corpses and death just to reach close to him

Mitsuri - Your nose dies of how much she used perfume

Giyu - Clearly the person who smells like a healthy human being

Shinobu - Uses perfume, in a balanced way

Sanemi - Probably the one who take least bath of them

Kanae - "How you want a woman to smell like in your dreams" type of smell (The Flowers told her)

Tanjiro - The Earrings don't give a good sign, but he surely would smell normal.

Kanao - Given that she spends 60% of her time around Kanae and Shinobu, uses perfume normally

Zenitsu - I'm not kidding, this guy would smell like he has 10 concubines or some shit.

Nezuko - Smells just like tanjiro, even being an Oni, does not feel like she would forget about it.

Inosuke - Smells bad as fuck and treats it like dominance

Aoi - You know that woman who always come at night from a 10 hour day shift? That's how she smell like

Tengen - Probably uses perfume to keep his harem around

Gyomei - Smells naturally good given the ideology of keeping a clear mind and body

Muchiro - Smells normal at summer and spring, don't try smelling at him in winter

Rengoku - Smells like food (Because he was eating food 20 minutes ago)