Duskers

During the 1800s there were two types of angels active: the agents as we know them now (though still in the early years) and Duskers.

Duskers were...to put it lightly, the reason people were afraid to go out at night, or into dark alleys (yanno, other than the normal reasons to be afraid of going into a dark alley). They were created at a time where it was still seen as a good thing if the angels didn't really have a public face and were all "here now, save you, gone again" - they didn't have their Clarkes for PR, they didn't have big shiny office buildings and they didn't have recruits.

[Conversely, the agents at the time were created from the train of thought that maybe it was time to step out of the shadows and integrate into humanity a little more].

They hunted the things in the dark by being as scary as the things in the dark. (If you've seen Hellsing, think a group of people along the same lines as Paladin Alexander Anderson if he'd stop quoting the bloody bible, and without the terrible accent). They'd hang around the dark places in their duster jackets (yes, they're Badass Longcoats) and shank any demon/fae/half-breed that stepped out of line/threatened another. They were a lot less subtle and a lot more martial law then the agents we know and love.

But still, they did their job well, and kept the streets safe (even if people were as likely to run screaming from a Dusker as they were from a demon).

Time went on, however, and it became clear that the bright-and-shiny agents were the far better choice, so the decision was made to have all of the Duskers destroyed.

Then something happened that had never happened before, they rebelled. They refused to go quietly into the night and be replaced by a breed of angel they viewed as weaker (mainly because bright-and-shiny agents wouldn't...yanno, shank someone who was running away). Because of their solitary nature, it was hard for them to get organised, but still, they ran and they fought (taking down quite a few bright-and-shinies while they were at it).

More and more agents were generated, and finally the rebellion was destroyed. (It still isn't known whether or not all of the Duskers were killed).

And just because I've been asked this before when talking about these guys, no, Jack the Ripper was not one of them. -_-