Ok, tamayo's drug just got way too convenient. Usually the hashira work with rather clear rules regarding what they can or can't do. As in, breaths techniques are in no form or context magical (so far), they are all just fancy ways to swing a stick of metal when you activate gear 2. Nichirin swords kill demons when you decapitate them with some exceptions. Red blades have special still not fully understood properties though they involve slowing down demon regeneration and perhaps leaving a more permanent wound in them. But then tamayo comes in and her medicine just does whatever. It feels like the author made muzan so powerful that he needed something to bail out the plot.
I can already imagine the next volume:
Muzan: Damn you tamayo and your drug with 4 effects!
Tamayo: kukuku, did you think I was telling the truth? Fascinating.
Muzan: So.... 5?
Tamayo: YES!!!!!!!! My drug has FUCKING FIVE EFFECTS!
Muzan: The fuck did you inject me with!? What's the fifth eff- *bark bark bark*
Tamayo: It makes you bark for a bit, obviously.
Iguro: Is he fucking barking?
Kaburamaru: Zzz, zzz'z, zzzz Z zz zzzz zzzzz (Dude, don't even, I am just a snake).
Muzan: bark bark bar- YOU CUNT!
Tamayo: Don't be like that, you are going to love the sixth effect.
Muzan:.... Did something happen? It doesn't look like something happened.
Tanjiro: Iguro! Watch out! Muzan just grew adorable cat ears, he is probably going to use a new form!
Muzan: FUCK!
I can already imagine the next volume:
Muzan: Damn you tamayo and your drug with 4 effects!
Tamayo: kukuku, did you think I was telling the truth? Fascinating.
Muzan: So.... 5?
Tamayo: YES!!!!!!!! My drug has FUCKING FIVE EFFECTS!
Muzan: The fuck did you inject me with!? What's the fifth eff- *bark bark bark*
Tamayo: It makes you bark for a bit, obviously.
Iguro: Is he fucking barking?
Kaburamaru: Zzz, zzz'z, zzzz Z zz zzzz zzzzz (Dude, don't even, I am just a snake).
Muzan: bark bark bar- YOU CUNT!
Tamayo: Don't be like that, you are going to love the sixth effect.
Muzan:.... Did something happen? It doesn't look like something happened.
Tanjiro: Iguro! Watch out! Muzan just grew adorable cat ears, he is probably going to use a new form!
Muzan: FUCK!