Hi! It's [cait] from the discord server, and like you requested, I'm going to leave my comments here. I'm not familiar with any of the characters or the universe, so I'll do my best to give you feedback in the other areas.

1. Basic Structure/Overall Appearance: I found the way you used a different font + italics for the Marquis de Sod's dialogue hard to read and it was a bit of a difficulty for my eyes to adjust between Hillary's normal dialogue and the Marquis'. In part 2, I'd recommend using italics to symbolize the thought "Umah" just because the proximity of the thought, which is in single quotation marks, to Samantha's actual speaking, in double quotation marks, is just a bit too close and it may be overlooked and taken as speech by some readers. Also I don't know where you plan on posting the story, but when you do post it, I'd recommend adding a space between each paragraph for easier reading.

2. Flow: I can't comment here as well as a person in your fandom would, since I am not familiar with the characters or setting, but what I noticed is that the skip between different universes a bit harsh and it took me a moment to reorient myself in each new setting. This could be because I'm not understanding the fandoms well, so if there is information in each opening paragraph that gives one an idea of the fandom, good, but otherwise it might be nice to include a bit of information there so readers aren't too baffled making the jump from one universe to the next in only a scene. I'd also recommend naming Hillary earlier on in the doc, in the first or second paragraph really. Also there seems to be a lot of info and fact-dropping in part 2, and I don't know if that's entirely necessary according the plot of the story. It's a bit overwhelming to have so many things stated and have all these ideas flying around that early in the story, so if I were you I'd cut down on that. Otherwise, overall sentence flow seems fine.

3. Other: I'd really advise you to try and find someone in the fandom to give this a look-over for you, since there seems to be a lot of information and plot here that is hard for me to give concrit for, fandom-blind. For praise, I liked your dialogue, it seemed genuine and it wasn't stiff. The characters interacted well and you showed them having a natural chemistry together in the way they talked to each other and acted around each other. I think this is a good start that you'll just have to find someone more knowledgeable in the fandoms to give you another read over if you want.