Here is the full list of all 20 Fox Spirit: A Two-Tailed Adventure achievements.
End the game as a fearsome demon.
Destroy the entire human empire.
Help the Wild Masters destroy Hoshimori.
Avenge your family by killing Daichi.
End the game as a beloved folk hero.
Join the Wild Masters.
Find the Star Ball.
Change Daichi's attitude toward foxes.
Put on a spectacular light show.
End the game with an enigmatic role.
Have an intact romantic relationship at the end of the game.
Have a very good friendship intact at the end of the game.
Secure a peaceful resolution to the conflict between the Wild Masters and the human empire.
Help the human empire destroy the Wild Masters.
Secure a job working for the human empire.
End the game as an infamous trickster.
End the game as a divine messenger of the Goddess of Hoshimori.
Stole an eel and then repented.
Learned about Chiyo's scar.
Beat Kahi at a game of tag.