Here is the full list of all 46 Conception PLUS: Maidens of the Twelve Stars achievements.
Complete main scenario.
Complete Normal ending.
Clear 12 Constellation Labyrinths.
Give birth to the special class "Dungeon Master."
Clear 6 Constellation Labyrinths.
Clear 4 Constellation Labyrinths.
Give birth to the special class "Sage."
Perform the Tri-Mating ritual.
Clear 3 Constellation Labyrinths.
Clear 2 Constellation Labyrinths.
Clear 1 Constellation Labyrinth.
Complete a total of 8 Chain Combos.
Have 25 Star Children go independent.
Insta-kill 100 Impurities.
Visited the Map Point "Gift Shop."
Visited the Map Point "Scavenger."
Visited the Map Point "Day Camp."
Give birth to 12 Star Children.
Give birth to your first Star Child.
Obtain all achievements.
Complete a total of 100 Chain Combos.
MECUNITE a total of 10 times.
Use all Team Colors.
Give birth to the special class "Ninja."
Give birth to the special class "Bondsman."
Give birth to a Star Child of each class.
Give birth to 200 Star Children.
Have 100 Star Children go independent.
Complete all quests.
Obtain all weapons.
Obtain all armor.
Obtain all accessories.
Complete Arie's ending.
Complete Tarua's ending.
Complete Lillith's ending.
Complete Ruka's ending.
Complete Femiruna's ending.
Complete Mahiru's ending.
Complete Mirei's ending.
Complete Reone's ending.
Complete Sue's ending.
Complete Farun's ending.
Complete Collette's ending.
Complete Yuzuha's ending.
Complete Alfie's ending.
Complete Harem ending.