Aboard the Atherum, the party discovers a locked red box. At Yormgen, Yuefan opens the box and reveals the clear ciel crystal, which she states can be used to form barriers. However, Duke Pantarei uses the power of Dein Nomos to cause the crystal to disappear. The party obtains their first apatheia, the cyano ciel crystal, when Belius dies. Rita Mordio later uses the cyano ciel crystal to convert the out of control aer into mana; in doing so, Belius is reborn as the Spirit Undine. From this point, the party plans to convert all apatheia into Spirits for the sake of eliminating the Adephagos.
However, creating apatheia takes time; Judith later states that Ba'ul has not consumed enough aer to form one. The group obtains the second apatheia from Phaeroh, who dies due to his wounds from the attack at Zaude; in doing so, he is reborn as the Spirit Efreet. They obtain the third apatheia from Gusios after he had consumed too much aer and was subsequently attacked by the Hunting Blades; in doing so, he is reborn as the Spirit Gnome. The group obtains the fourth and final apatheia from Khroma after she willingly fights them and dies; in doing so, she is reborn as the Spirit Sylph.