Another great update, Talothral!
I read several VNs, but I don't even bother trying to proof-read most of them because it would be an excessively arduous task. Yours have so few errors that review is quite feasible. In the end, I see this as a small contribution to a VN that we all get for free.
I only found a few places to submit for further review:
Lilmina addressing Tomas in bed: "...could have done with a post checkup activity..." This isn't exactly wrong, it just seems awkward to me. Maybe something like "...could have engaged in other activities following the checkup...". Also, a skilled writer like yourself understands that people don't often speak in complete sentences or with the degree of grammatical correctness and clarity that we can achieve with written communication. Given this is a verbal exchange, maybe some ambiguity or awkwardness is desirable.
Naked Lilmina and Lian kissing Tomas in bed (Lilmina speaking): "Let's see does the potion work like it should." There are two possibilities immediately evident here. "Let's see; does the portion work like it should?" or "Let's see if the portion works as it should."
Discussion between Tomas, Lilmina and Lian on the bed after the animation, Lilmina speaking: "Told I would get you." potentially missing a 'you'.
Discussion between Tomas, Lilmina and Lian on the bed after the animation, Lian speaking: "...I don't know in what kind mood the Empress is in after the sentencing..." This one is a bit tough; I doubt that the Empress' mood is expected to be kind, so potentially, "...I don't know what kind of mood the Empress will be in after the sentencing..."
Rielle addressing the group, specifically Tomas: "... So how should I call you?" Probably either "... So what should I call you?" or "... So how should I address you?" I thought she was referring to a magical artifact analogous to a telephone before I read the response.
Tomas replying to Rielle: "I don't expect you or anyone of you suddenly start using titles." "I don't expect you or any one of you to suddenly start using titles." reads a little better. I read 'anyone' as referring to a non-specific but singular person from the subset of all people, not a reference to a non-specific but singular member of a specific group. (Also note the 'to').
Shani addressing the group in the scene where they all converse with Rielle: "...when we are among us, we are like we were. Out there?". Not knowing exactly what was intended to be said, this may be a terrible correction: "...when we are together, just us, we are like we were out there."
Uche talking to Tomas: "...no wires not raised flooring or pressure plates, nothing." I think that 'not' should be 'nor'. Alternatively, "...no wires, no raised flooring or pressure plates, nothing."
Tomas talking to Uche: "Planning on going to North then?" Possibly "Planning on going North, then?"
Tomas talking to Uche: "I took over a former archmages tower..." Probably 'archmage's'.
Aria talking to Ayaka while siting on a crate: "People don' change just like that." Unless this is a accent (which would seem inconsistent, given the rest of the dialog), this is probably supposed to be 'don't'.
Eirlys talking to Tomas: "... She was going to go to Tomas..." Isn't she talking to Tomas? I'm guessing that she really did intend to go to Tomas (hence the seeker scaring her away), but in this case, she would have said 'you'.
Eirlys talking to Tomas: "...preparing his, any my soul..." Probably 'any' = 'and'.
Recognizing that punctuation is read differently by different people, none of the suggestions above regard punctuation. It is likely that a strict English teacher would recommend use of more semicolons instead of periods, but I doubt that many among the target demographic really care to that degree. Commas are similar; some may be placed where a pause would be strange, while others are missing where a pause would be expected.
Note: In some places 'North' is capitalized and in other places it is not. It doesn't really matter, but you may want to choose to capitalize or not and make this consistent.