Here is the full list of all 20 Eudemons Online achievements.
Kill 1 Mad Bull outside Cronus.
Use the Red Stone to intensify equipment once.
Complete the Main Attribute Composing once at the Composing Center.
Use the Metaspace once on the Eudemons interface.
Embed a gem on your equipment.
Upgrade an Eudemon to 5-star by ways like Main Attribute Composing.
Unlock a Goddess through offering a Sacred Tribute.
Complete 1 Goddess Embrace on the interface of any Goddess.
Summon a servant and make a Goddess Material.
Add 1 friend on [Social] - [Friend] interface.
Join 1 legion on [Social] - [Legion] interface.
Appoint 4 Eudemons as Guardian, Dervish, Templar and Cleric.
Practice your skills to upgrade.
Equip the Berserk Horn.
Complete Pre Apotheosis Quest and pass the Apotheosis challenge.
Complete Divine Main Composing at the Composing Center.
Upgrade an Eudemon to 20-star by ways like Main Attribute Composing.
Summon 3 Eudemons simultaneously or use the God Eudemon Stone to open 3 Eudemon Slots.
Use the God Tear to upgrade your equipment to Divine Equipment.
Use the Holy Summon to apotheosize your Eudemons.