My working model for how Hariel knows the Lord Reverend ir'Irandi (by the way--what is the proper mode of address? His Reverence? His Grace? Lord Reverend?) depends a lot on what kinds of projects he's been involved in in the past. Based on the short description we have, I've presumed that he might have been involved in charity works in the city of Flamekeep. I've also presumed that he might have been involved in the government of Flamekeep, or of Thrane, at some point.
Working with the most optimistic situation, I believe Hariel was a bit of a street rat in one of the poorer areas of Flamekeep when she was young. The Lord Reverend was involved in some way (anything from simply lending his name to the enterprise to direct involvement) in a project to provide help to the needy in these areas, and particularly, in a project to educate the poor youth. Hariel turned out to be one of the brighter students, and ended up joining the Flamekeep constabulary when she came of age.
The next step is somewhat more tenuous: I feel that the Lord Reverend is a man with a mind for seemingly trivial detail. What I imagine is that Hariel discovered some corruption in the guard, and when she attempted to call attention to it, she was framed for the crimes herself--the actual corrupt guards assuming that because she was from one of the poorest and most crime-ridden parts of town, nobody would give her case a second look. By chance, the Lord Reverend was in a position to hear about the case, and recalled Hariel's name and circumstances. Based on what he knew about Hariel (either first-hand, if he was involved in the charity work directly, or second-hand, if he received reports of the work), he had doubts that Hariel was guilty. After some amount of work (on the part of Hariel and those she worked with directly, who had come to respect her a great deal), and with the Lord Reverend's interest (which may have not been directly obvious) to ensure that someone was listening, Hariel was cleared--and now doubly indebted to a man (possibly a man she had never actually met.)
After she was cleared, Hariel was promoted from the equivalent of a beat cop to a detective. Her keen intellect and her willingness to take direct action to bring the truth to light spoke well for her. Not to mention the fact that people were now willing to overlook her low origins... and that she perhaps had patronage (either people believed she did, or she did publicly, or she did quietly without truly knowing it.)
Naturally, when an agent of that man delivered a message requesting a meeting, and perhaps mentioning the Lord Reverend's interest in her recent case, Hariel was happy to oblige. And that lead to him suggesting some things she might look into for him.
I like the background of having some public recognition in this way. Should be an interesting mix of respect, admiration, and "who does she think she is, anyway?" sorts of attitudes from different groups of people. But I'm not super attached to this backstory if it doesn't fit the Lord Reverend's style. Either of the two situations (the charity, or the quiet patronage in the case of corruption) would do alone, as would anything similar that would make Hariel indebted to the Lord Reverend--and that would cause her to believe he's a man worthy of respect.
As for how our characters know each other, it seems to me that the easiest way would be for us to know each other through the Lord Reverend. It's possible that some of us have been brought together by him to work with each other over the last few years. Perhaps all of us have worked together with some of the others, but not all together at once.
Once we get things penciled in in a little bit more detail, perhaps we could learn something about what we've done for the Lord Reverend in the past? I've restricted my speculation to how Hariel came to know him, but I don't want to speculate into what he would have asked her to do. (Although the thought strikes me, depending on how the Lord Reverend operates, that Hariel may have been set on the trail of the corrupt guards by the L.R. without knowing about it.)
Anyway, that's enough for me, now. I look forward to what other people have to suggest.
