Yuusha no Sensei, Saikyou no Kuzu ni naru. ~S-kyuu Party no Moto Eiyuu, Ura Shakai no Ihou Guild de Nariagari~

The hero's teacher, hero Maxima, has become addicted to alcohol! Gambling! Alcohol! And mounting debt! He's literally given the status of "scum" and kicked out of the hero's party. With the help of his debt collectors, Maxima ends up setting up an illegal guild—but how? He'll rise to the top illegally in an illegal guild!