In EO, the loyalty decides whether you can summoned your eudemons or combine with it.
When the loyalty is 50 below, you cannot summon it.
When the loyalty is 80 below, its level up will decrease its quality.
When the loyalty is 100 below, you cannot combine with it, and it won't get a talent reward.
Only when the loyalty is 120 above, you can login Eudemon Profile and use some advanced combine skills and the star light effect will appear.
When the loyalty is 150+, if the player's HP is low, the player's damage will be converted to the eudemon, to show its loyalty.
When will the loyalty increase or decrease?
Increase:
1. Keep the eudemon with you
2. Summon it in fight, its level up will increase its loyalty.
Decrease:
1. The eudemon is killed or dead.
2.Exchange it with others, the exchange will cause a decrease of loyalty.