Here is the full list of all 24 The Impregnation of the Elves: Conquest of the Arrogant Fairies by Impregnation achievements.
Achieved Ending 1
Victory over Idun
Defeated by Idun
Destroy Idun's armour completely
Victory over Frigga
Defeated by Frigga
Victory over Nimue
Destroy Nimue's armour completely
Defeated by Nimue
Victory over Vivian
Destroy Vivian's armour completely
Defeated by Vivian
Victory over Nineve
Destroy Nineve's armour completely
Defeated by Nineve
Victory over Dryad
Destroy Dryad's armour completely
Defeated by Dryad
Passed a question once
Achieved Ending 2
See the Goddess' True Form
Destroy Frigga's armour completely
Unlock all achievements
Defeat all the Elves in Challenge Mode