I really like Zaruthustran's idea. I'd start mixing in known threats to give it a little definition. That would seem to be something Titivilious would be involved in, perhaps he originally tempted that fallen solar (who brought buddies down with him). Then again, he could
be the infernal solar in question.
Regardless, the Good Celestials, may encountered while fighting either the flies or insect groups (perhaps both). This would be something they do often, considering it their mission in life to overcome these agents of Pestilence and Famine(?) before they can spread across the Prime, helping to bring about Armageddon. They believe in two ideals:
- As Zaruthustran, they believe themselves to be the epitomy of Goodness and see their master(s) as the source of such radiance. But they're fanatical about it. They won't question their belief system, ever, despite what it may ask of them. On the far side of the Law/Chaos axes, they stick to their own personal cursade in life. They don't get involved in other's battles, even at no risk to themselves. The young woman being dragged into an ally, the politics of this or that city, or the rise of an undead legion are simply not their concern, regardless of the personal risk (or lack there-of) involved.
- Death has already arrived on the Prime. There's no use fighting against it. Such a fight would only bring about more Death. As such, fighting Famine and Pestilance will have to serve to hold back the end of time. The same with War.
Behind it all, of course, are the Liars. Those Courtiers of Perdition, raised up by Asmodious Himself, for the sole purpose of taking control of the Prime. This group, while always waring with itself to some extent, holds great sway over the other three, who unknowingly follow the Liars' plans.
Each miner group believes they have a grand destiny, handed to them by Fate itself. Indeed, they do, though Fate has little to do with it. It's merely not the destiny they envision. The Lords of the Nine seek to send the Flies and Insects across the Prime, bringing War and Death to all the great nations and churchs. It's their goal not to scour the Prime, but to weaken it enough to allow for a true invasion from the Nine Hells.
Thus the involvment of the third group; those who think themselves saviours. It's their role to act as a counter to Famine and Pesilance, keeping them gaining enough strength to truely crush the mortal realm. In addition, when such a War finally takes place, the Celestial group will appear to be handling the situation. Thus, the Lords hope, the Upper Planes will not see it necisary to get directly involved.
Naturally, such a balance isn't easy to maintain. There are constantly necessary adjustments being made to all sides. A tip-off to one group, a trap set off on another, or, rarely, wiping out an entire base/hive/colony.
The Liars, of course, never want to reveal themselves. Instead they tend to act through intermediaries. Unwitting intermediaries with a penchent for meddling, a reputation for success, and a willingness to move on after they think they've succeeded.
Thus, the Defenders of Daybreak are a perfect choice.