Here is the full list of all 23 Moonchild achievements.
Talk 16 times
Calypso - Lv 50
Calypso - 1000 kills
Om - 666 kills
16 hours played
Susanna - 200 magic kills
Jardel - 100 magic kills
Jardel - 100 kills
Om - 100 kills
Dabbabbu - 100 kills
Rupert - 100 kills
All quests completed
100,000 gold coins
10,000 gold coins
30 creatures summoned
Susanna - 100 kills
Kenneth - 100 kills
Stardust - 100 kills
5 quests completed
Gabriel - 100 kills
Calypso - 100 kills
2,500 gold coins
1 hour played