Eart Soul Orbs, also known as ESO, are items that can be used to level up your sperion. Leveling a sperion 


Stack of ESO

makes it more powerful and also allows it to be morphed by using soul prints and purified crystals once it has reach a high enough level.

It takes 25 sperion to increase the sperion experience once, and each experience increment is about half the level up bar.