Fibrill is a manifestation of power synonymous with the Divine Aurora and Dark Aurora artes, being capable of both creation and destruction. The creative side of Fibrill, the Divine Aurora, is the direct power of Seyfert, the god of creation who fashioned the worlds of Inferia and Celestia, while the destructive side of Fibrill, the Dark Aurora, is the direct power of Nereid, the god of destruction who once ruled the non-material realm of Vatenkeist. Both forms of Fibrill are capable of being passed down to humans; while Nereid typically uses hosts to transfer power, Seyfert passes down power via trials that award those who succeed with powerful artes.
Although these two types of Fibrill contrast each other, they are never defined as good or evil despite their properties. Certain conditions must also be in order to receive the power of Fibrill. Nereid tempts hosts who are full of despair, such as Shizel when her husband, Transon Balir, died in her arms; her desire for a world without the pain and suffering she experienced spurred a desire for destruction of the material world that caused it. Shizel gave her heart to Nereid and was an ideal host for his plans; she herself mastered the Dark Aurora artes over time by experimenting on Hyades and Meredy, blood relatives who were bestowed with the Fibrill as well. On the other hand, Seyfert offers trials for his power, and those who pass these trials seem to have a desire to protect others.