New Dawn

New Dawn is a paradoxical group of mages who seceded from the Imperial Magic Guild de to their deep seated hatred for magic. They are born from people who survived some traumatic events, and from mages that decide to believe in the theory that the Lost Lands are a proof of the Prime Material World being on the verge of breaking and changing into a Spiritual World. And not only believed in it, but also decided to do whatever they can to stop this scenario from playing out.
The New Dawn is a relatively recent addition to the list of the Magic Guild' seccesionists, as their little schism occured barely a century ago. It happened following a short series of significant disasters in the imperial struggle against the Lost Lands that happened to coexist with the creation of the theory mentioned above. Most mages remained unconvinced by it, by many decided that it's actually true and requires significant and powerful counteracting.
The New Dawn is mostly staying under the imperial radar since then. The Grand Empire is strictly monitoring its attempts to develop new means of antimagic and of lowering the level of ambient mana in environments. In fact, some go as far as to suggest that New Dawn has an under-the-table support from some high-ranked individuals within the Grand Empire, with only the Imperial Magic Guild going through some actual effort when it comes to combating the New Dawn operations.
Recently, however, the entire modus operandi of the New Dawn appears to have been changed. There were several semi-confirmed cases of its attacks on imperial infrastructure, most done as a part of looking for some data (and gathering of rare resources). The reason for that - and if it's truly the New Dawn's work - is unknown.

Structure

Like in case of almost all other schismatic groups from the Imperial Magic Guild, they have a central hub of operations in the Lost Lands, and a handful of undercover cells in the nearby province. They use adventurers as messengers, and have their 'cells' provide them with money, workforce, resources and intelligence. It should be noted, though, that perhaps due to their relatively recent secession they maintain a traditional Imperial Magic Guild's internal structure (including the mostly egalitarian if meritocratic decision-making).
This does make a certain degree of sense, as majority of the New Dawn mages considers itself to be a 'Imperial Magic Guild's in-exile', although it's hard to say if there wasn't a change on that field due to their recent attacks on the Grand Empire.

Military

The biggest problem with the New Dawn's operatives is that they are extremely skilled in countering magic. They can suppress it in their surroundings, even if temporarily, which is often enough for them to simply walk over to the powerful loyalist mage that engaged them in combat and slice his throat with a very mundane danger. The way it works can typically be described as percentage suppression, with the stronger the New Dawn operative (or the more of them in the area), the more percent of their outcome strength locally casted spells lose.
Their mages are also capable of channeling this effect into projectiles and AoE spell-equivalents, that suppresses not only regular magic but also martial arts. Until recently, only the theurgy remained untouched, but reports from recent engagements with the New Dawn forces claim that this too changed, although they are significantly less influenced (by about half). If that wasn't enough, they also have access to materials with similar properties (although they tend to be far weaker than antegnite).
As a result, any larger group of New Dawn will simply deactivate all magic and banish all daemons with their presence (while potentially killing more magic-natured mortals). What's left is them and their enemies trying to bash each other's head with some decidedly mundane means. Although it's only the New Dawn members that get routinely trained for such bashing, meaning that they naturally hold the advantage.