All I gotta say is that this novel of yours has a striking resemblance to MTWABV, the best example of this when Vergil and Sapphire met each other like Victor and Scathach but in a much better way. And also how he met Ada, Katherine, and Roxanne which is also pretty similar to how Victor met Violet, Ruby, and Sasha and it's also the fact that both of them are battle maniacs. But this is definitely better than the start of MTWABV in my humble opinion since Vergil's father is dead, and some of you may relate to this because- well you might already know what I'm talking about... So anyway, so far so good and I'm glad the harem won't be that big since as you have said that only 9-16 members will be in his harem if I remember correctly (or maybe it will get bigger but who knows?) and the grammar is also much better than MTWABV but I'm no expert because my English is average at best since it's not my first language either but it's definitely better.
(I won't mind Felicia ({Vergil's mother}) getting in the harem since there's no father in this one but the others might not like it or maybe they will because I don't see any man as a perfect fit for her ({for now that is and this is also my lower part thinking}). And since she's still single I most preferably prefer that she stays single if you don't plan on putting her in the harem but this ain't my novel so who am I to say this?)
Anyway, this is my review without actually saying what made this better than MTWABV or how the story actually goes but I'm too lazy for that🤣.