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.
Defeated Harina.
Acquired the Frailty Incense.
Purified Princess Poeme.
Collected all the archives.
Executed a total of 1000 witches and enemies.
Purified the witch deity Parushee.
Purified the Witch of Lust.
Collected a total of 20 silver coins.
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.