Here is the full list of all 16 Demonheart: The Ice Demon achievements.
Reach a happy ending with Sirath.
Be saved by Nissa.
Be saved by Zhan.
Have a secret affair with Sirath.
Make a mess on Eniri's desk.
Bring Esmius some wine.
Defile the Mistress's bedroom.
Be saved by Eniri.
Save yourself with dark magic.
Lie to Mother.
End up somewhere you didn't want.
Reach a happy ending with Esmius.
Reach a happy ending with Nissa.
Become the mistress of the house.
Learn Nissa's real name (I).
Learn Nissa's real name (II).