Did we really need an entire chapter devoted to telling us that he's a wretched person? We already knew that. We've seen enough hints that we don't need this entire chapter devoted to it and the horrible acts he's about to commit. Acts I'm sure you'll show the after effects in the next chapter...uhg.
I'm quite sure that all these sisters, especially Jinny, aren't just being introduced to show how despicable Father Ram is. This whole arc isn't about Father Vincent gaining power to burn the entire Church down with everyone in it: it's about revealing the truth of their false god and their corrupt leaders. These sisters are probably going to end up joining Vincent's faction—likely after he saves them somehow. And it's not like they came out of nowhere: we've learned about how Mother Letna, Sister Vanessa, and Father Ram had been their caretakers, so it makes enough sense for them to receive proper introductions now.
A chapter dedicated to introducing characters we've heard about for a while and who will likely be significant going forward sounds totally appropriate. I'm not sure why you're assuming they are only here to have horrible things happen to them.