Flames of Fate, commonly abbreviated to FoF by the Alliance, are what appear to be an elemental/chemical compound of arcane potential. All characters within the Devil Beater Universe use FoF, though some character who don't seem to fit in any catalog of the main 7 are using an isotopes element which contain more then one portion of an element in them.
Using FoF appears to be something that can be treated as an art, as there are users that look like but may not necessarily be novices in the usage of FoF, while Sig and Derek are adepts in it, and can bend the compound to much more than just its pure form; in addition, Domino admits to wanting to replace his knives with FoF blades, which arguably furthers this theory.
Flames of Fate have two ways to manifest: Concentrated FoF can appear in liquid form, seen spewing out of a broken pipe Gardi Nakara told Maurice Altara to smash as a prank. When a person using FoF casts an attack using it, they take on either a more ethereal pure form, or gas.
Either way, FoF has the appearance of large grouped squares, giving the sense of advanced arcana when used.
In act XLVI, the protagonist finds a diversity of FoFs within cylindrical tubes on the wall. Noticeably, there is a unique kind of FoF in the group, with the ability to rapidly change color. It is suggested that a wielder of this element is Xor. Though the element's volatility in color also resembles the element wielded by Seth Nasmeth.
It is likely that most characters uses the Flames of Fate. However, there are some character that do not use FoF, such as Rufu Ray and Kiseki Kaboko.