Revived my dynasty scans account to post here. I've been bad at keeping up with all the yummy great yuri manga updates, so I was pleasantly surprised to see this has had 8 chapters since I first read the opening chapter.
I'm also surprised no one has commented on the obvious connection of Mimi's mother being the one who was sacrificed to resurrect her daughter, and Shiina's motherly actions towards Mimi (as pointed out by Ari and Seiran, and pretty much every single page Shiina and Mimi are together.) It made me wonder if Shiina is possibly a descendant/relative of Mimi's mother/bloodline.
side note: Seiran is literally me in regards to anything that happens involving Shiina, I screamed out loud when both Mimi and Shiina's numbers were called out (cue Seiran standing up and yelling SHIINA!!!!!)
I think the nurse is pretty confident in how things will turn out regarding Shiina's knowledge of the forbidden magicks and the other senpai knowing that she's scheming something. Her healing ability and experimental tendencies (like when she just told Mimi to heal herself instead of the nurse doing it, as Mimi has referenced before) are likely related to Shiina's roommate's death (isn't it suspicious her roommate dies just as Mimi comes along and needs a roommate?), and Shiina meeting up with Mimi and the nurse in the first chapter before the big reveal (nurse must be planning something big time).
Next concern is Ari and Seiran... why did Seiran speak of doing a resurrection spell, right in front of Ari's eyes? The first read makes you assume it'd be that Seiran would sacrifice herself for Ari, but doing it in front of her eyes seems to imply that Ari would still be alive? and if so, why would Seiran be speaking about a resurrection spell, unless it's not? What if it's some other forbidden magic spell we don't know about yet? (like, the story hasn't revealed it to us yet, but the students have learned about it already) hohum so many theories.