How do I get more erolins?

[Ungod]

And what are they useful for?

[MaGoHi]

you can buy them in the MD shop

they are a way to store erolin heat

Spoiler

erolin heat is needed to cast spells, to fill some clickies to activat their effect or to increase the stat gain in combat, if you are Adept to someone you can also pray this heat to them in exchange for loyalty points