Here is the full list of all 12 Guardian Chronicle achievements.
Win a battle 10 times
Win a battle 100 times
Comebine guardians 100 times during a battle
Comebine guardians 1,000 times during a battle
Summon a guardian 100 times during a battle
Summon a guardian 1,000 times during a battle
Use 10,000 gold
Use 500,000 gold
Open a chest 10 times
Open a chest 100 times
Obtain 50,000 battle coins
Reach account level 3