Although the Nathrezim lost much of their power when several of the more influential members fell to Her forces ultimately most were defeated, not destroyed. Indeed, to this day Varimathras precise whereabouts remain a mystery. The dreadlords are masters of guile, trickery, and deceit who prefer to remain and act from behind the scene. Only the foolish would presume that just because they cannot see something it must not be there.
To that end the Queen has commanded me to re-organize the Warlocks within the Order. They will be charged with guarding against the Nathrezim's return as well as eliminating any demonic influence that seeks to subvert the Crown. Henceforth they will be known as Felbreakers.
All of the Order's class-based ranks are rooted in lore to one degree or another and the Felbreakers are no different. Both in name and in concept they are similar to Sin'dorei Spellbreakers.
Spellbreakers are an elite blood elf unit that excel at battling other casters. They have mastered the arts of spell craft to such a degree that they have become immune to the effects of even the most powerful magics. This, coupled with their fierce combat skills, makes them implacable foes when facing magic-wielding enemies.
The Order's Felbreakers will be cast in much the same mold. Power corrupts and absolute [demonic] power corrupts absolutely. Those aspiring to be one of Her Majesty's Felbreakers however must prove themselves adept at not only wielding these chaotic energies but demonstrate that they can control them, not be consumed by them. There is an old saying ,"do not call up that which you cannot putdown." Truer words were never spoken.
If the Nathrezim return, someone must deal with them. And if a fellow Undead goes " Kanrethad Ebonlocke" on us, someone must take them out.
(The Black Harvest reference brings up an interesting point that I do want to clarify. It is not my intent to change the process by which an Initiate's days of chewing rocks are over and they are promoted to full fledged member status. It would be wrong to raise the bar for one class alone. I've been farming Sealed Tomes of the Lost Legion though, and I do intend to do something 'on the side' for Felbreakers as a rite of passage, if only help them get started on the green fire quest chain.)