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