There's just one problem.

Their creator hasn't been a Cherub for twenty thousand years.

A Cetherite's resonance is for danger. They can determine whether or not a given human is in trouble, whether or not that person will be soon, how much trouble, and sometimes even exactly what kind. Cetherim always seem to end up finding those who most need their specialized help.

Cetherim suffer dissonance whenever they abandon those that they have determined to be at risk. They may not be able to keep those whom they have resonated alive and healthy, but they must stay at that person's side until the crisis is reached and resolved. Consistently avoiding the use of their resonance is also grounds for dissonance, and is ultimately futile: a Cetherite that does not master his ability will find that it manifests without warning.

Cetherim don't really pay too much unnecessary attention to their earthly vessels. They prefer to be neat, clean and fairly attractive (it's practical), but they don't bother much with frills. Cetherim tend to come across as driven, loyal and a touch paranoid, although "paranoid" may imply a mental instability that isn't actually there. When a Cetherite thinks that the whole world is out to get him (or his charge), he's usually got an extremely good reason for his belief.

In their celestial form, they appear as a near-transparent cloud of vapors, often with a vaguely humanoid face. One can walk right through a Cetherite without ill effects, and indeed without offering any kind of insult. They get along pretty well with Cherubim and Kyriotates (both of whom have their own problems with protecting fragile mortals), but their lack of self-identity tends to confuse Mercurians. Cetherim have issues with Malakim.

It can be hard for a Cetherite to stand the distance. Those who can't handle being the shield of a mortal, for whatever reason, may find themselves either avoiding the task completely, or else smothering their charges by keeping them from all possible dangers and never letting them stand up on their own. These angels run the risk of Falling and becoming Solipsists, a Band dedicated to making individual humans stronger at the expense of everything else in the universe. Unlike Cetherim, Solipsists are well regarded by their principal creator (Malphas), even though a Solipsist is fairly prone to Redeeming if he ever goes Renegade.

A Cetherite may only use her resonance on humans. The angel must normally make hand or eye contact (see below). As a general rule, the angel will not be able to tell with any precision the exact moment when disaster is going to strike. Cetherim do know when their subjects are out of danger, but there's no way, short of continuous use of resonance rolls, to keep constant tabs on a person.

1. You can see whether or not the subject is currently in danger.

2. As above: you also know whether the subject is going to be in danger within the next 24 hours.

3. As above: plus, if the subject actually is in danger at that moment, then you have an idea of what kind, and what the likely consequences could be if left unchecked.

4. As above, except that you will be able to determine the nature and consequences of dangers that will arise within 24 hours.

5. As above, plus you gain some idea about the best way to minimize the effects arising from a specific danger.

6. As above, plus you know the best way to have the subject avoid the danger completely.

A Cetherite can attempt to resonate at a distance. He is at -2 if he can hear but not see the subject, or -4 if said subject is on live TV. Resonating via a photograph is at -6.

Even when not actively using her resonance, a Cetherite maintains a fine eye for imminent mishaps. These angels have a knack for being in just the right place to help someone else avoid embarrassment: this translates to "A Cetherite may gain a permanent +1 reaction from a specific person if she makes a successful Perception roll at -2".

After his transformation, David considered this Choir to be an anachronism. An honorable, venerable anachronism, to be sure, but still fundamentally wrong in their priorities. He has refused to create any new Cetherim since the Fall. In the meantime, angels are still angels, and should be permitted to offer their services to Heaven, no matter their flaws.

David expected this Choir to eventually wither and fade away on its own. What he did not quite realize is that Cetherim are stubborn, even for putative Servitors of Stone. The Choir collectively concluded that if anyone had trouble with priorities, it was their nominal Archangel … and that it was their duty to God and humanity to survive and serve. If David found their continued existence an embarrassing reminder of those days when he wanted to protect humanity, not beat them into shape, well, that's an added benefit. Considering their usual self-effacement, this was an amazingly assertive attitude to take.

As David declined to pass on the trick to making new Cetherim to anyone else, they gravitated towards those Superiors willing to assist celestial reproduction. These days, this mostly involves Novalis, though Michael and Zadkiel have respectable contingents. Eli was willing enough, in the past, but he's not usually available anymore. There are many Cetherim out there who have never even met David, and couldn't care less if they ever do.

Those few who stay with Stone (often called Mogenim) do so from personal loyalty to Stone, not because they agree with David (the last one that did died of despair a long time ago). They tend to be older, sadder, and have few offspring. Two Cetherim of Stone who wish to produce issue usually seek out Gabriel: for some reason, she has been known to agree to assist Cetherim, and David does not strenuously object to her meddling. Most "newborn" Mogenim leave for other Superiors very quickly.

Ironically, the only Cetherim that can advance in David's service these days are Redeemed Solipsists: while they may have an archaic resonance, these new angels often have priceless information on Infernal plans, and can thus partially rise above their inherent limitations. However, David only rarely gets them, unless he personally handles the Redemption: Novalis would rather see anybody else get their hands on members of this Choir (even Michael. Actually, Michael's a good choice for the more rambunctious ones). And, seeing that Novalis is the default Superior picked to guide Redeemed demons through the rough spots, David's between a rock and a hard place on this issue.

Those who serve Novalis may use their resonance on plant life. For 2 Essence, they can detect danger to their subjects up to a week before it happens: for 6 Essence, they can detect danger that's a year away. Dissonance conditions remain unchanged. Many Cetherim of other Words have this Attunement.

These angels are literally shields: if fighting alongside a mortal to whom they are currently resonated, the angel may replace the human's Dodge skill with his own. However, any attack on the mortal that fails solely because of the boost to Dodge will affect the Cetherite instead.

Zadkiel is doing her utmost to discover how to create Cetherim. She grants those who come to her (and she gets more than any other) with the ability to tell whether or not a danger detected by the angel's resonance is due to celestial meddling.