She's a high-ranking Church official and Shepard who runs the observation faction—basically the supernatural surveillance wing. Both Gabriella and Simon answer to her.
Simon's described her as the type who doesn't sweat the small stuff. She doesn't hound him over report details and apparently has no interest in creating busywork by sending auditors out to check on people. She seems content letting Simon stay where he is, positioned near Elias, and she gives Gabriella a pretty free hand to do her thing. Fans often note she's got a blunt way about her, but both Simon and Gabriella respect her, and it's clear she looks out for Simon in her own way—even if she's not warm about showing it.
Content compiled by AnimeList.moe from publicly available sources.