Here is the full list of all 15 Minoria achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Abandoned your mission in favor of the witches.
Defeated a major enemy without taking a hit.
Acquired the Frailty Incense.
Collected all the archives.
Defeated Harina.
Executed a total of 1000 witches and enemies.
Purified Princess Poeme.
Purified the witch deity Parushee.
Collected a total of 20 silver coins.
Purified the Witch of Lust.
Defeated Frikka, leader of the thieves.
Purified the witch deity Saora.
Warmed up Almu, the slug girl.
Purified Sister Devoir.
Rescued Princess Amelia from a group of witches.