Tokyo Revengers x (Tokito Muichiro) Reader

M/N Tokito is a decendent of the Tsugikuni family . Even if the demon king has been killed in taisho era , a secret was known in the Tsugikuni family , and it's that Kibutsuji Muzan has a decendent , so even if the demons had not been seen since over 100 years M/N's family trained and he still learned breathing techni...