Here is the full list of all 67 Crystal Maidens achievements.
Own 5 maidens
Complete level 1 of Campaign Mode
Complete level 30 of Campaign Mode
Complete level 60 of Campaign Mode
Own 10 maidens
Own 15 maidens
Get a hero up to level 10
Get a hero up to level 30
Get a hero up to level 60
Find a legendary item in the Campaign Mode
Earn 5000 coins in Campaign Mode
Earn 250.000 coins in Campaign Mode
Earn 1 million coins in Campaign Mode
Complete 10 quests
Complete 50 quests
Complete 200 quests
Upgrade a building up to level 2
Upgrade a building up to level 5
Upgrade a building up to level 10
Win 5 battles with all 3 stars
Win 20 battles with all 3 stars
Win 50 battles with all 3 stars
Kill 100 enemies in battle
Kill 250 enemies in battle
Kill 1000 enemies in battle
Play 50 battles with Support class
Play 100 battles with Support class
Play 500 battles with Support class
Play 100 battles with Engineer class
Play 500 battles with Engineer class
Play 50 battles with Warrior class
Play 100 battles with Warrior class
Play 50 battles with Marksman class
Play 100 battles with Marksman class
Play 500 battles with Marksman class
Play 50 battles with Mage class
Play 100 battles with Mage class
Play 500 battles with Mage class
Romance 2 maidens to level 3
Romance 5 maidens to level 3
Romance 15 maidens to level 3
Upgrade a skill to the level 5
Upgrade a skill to the level 20
Play 7 days in a row
Play 15 days in a row
Upgrade 1 common item to the level 5
Upgrade 10 common items to the level 5
Upgrade 30 common items to the level 5
Upgrade 1 rare item to the level 5
Upgrade 10 rare items to the level 5
Upgrade 30 rare items to the level 5
Upgrade 1 epic item to the level 5
Upgrade 10 epic items to the level 5
Upgrade 30 epic items to the level 5
Lose 50 battles
Lose 100 battles
Lose 500 battles
Earn 60 stars in Campaign 1
Earn 120 stars in Campaign 1
Earn 180 stars in Campaign 1
Find 5 legendary items in the Campaign Mode
Find 10 legendary items in the Campaign Mode
Upgrade 1 legendary item to the level 5
Upgrade 10 legendary items to the level 5"
Upgrade 30 legendary items to the level 5
Play 50 battles with Engineer class