[quote=Dynamics]
She just mentioned it.
[/quote]

That's the name of the Guild. We have two beast slayers. They are different from other Slayer magic in which they not only use elements, but they also use the power of the Legendary Beast that they learned from. Basically become were versions. Or even the beast itself. There are only seven Legendary Beasts. Each are from the Seven Vices and Virtues.