I just don't think we needed a whole flashback chapter introducing and characterizing someone who's already dead just so that we can have a path forward with our story. It's sloppy and breaks the pacing.
That's why I called it a nothing burger, majority of the chapter is introducing a character and his relationship dynamics when said character has been dead for a long time. The only thing here worth mentioning is the superficial connection between the Hero and Cecilia (giving her some pastry, mind you).
All of the other talk points (Kiara and the Demon King's character, etc) could have been explored through a chapter where things other than a ~20 pages flashback happened.
And I would argue the necessity to hammer down even more that Kiara is just battle obsessed and doesn't care about war and that the Demon King is innocent, with how stereotyped they were characterized up until chapter 7, it would be a twist if Kiara did care about the war and the Demon King is actually just evil.
I still don't think I agree with the argument you've presented here, though having your actual thoughts instead of a vague take at least lets me focus my own.
Reva is clearly an important character. She just so happens to be presently presumed dead, though that happened off-screen, in a setting where we've already been shown that information spread among humanity can be suspect (intentionally or otherwise),
and with a goddess who will interfere and resurrect people as it fits whatever aims she possesses. It's not outlandish to think this would apply to her Blessed Hero, and the goddess herself is suspect at this point, on top of that. Whatever her aims, Cecilia indicates in this very chapter that something is off where "humanity's hope and salvation" is concerned. It's an assumption that steps into meta-storytelling, but I'm not convinced that Reva is actually dead, or at least she is not permanently gone from the story, precisely because of how important she is on multiple fronts.
Primarily, Reva needs to be established as a full character & presence in the story & setting, because of her importance to Kiana. We see *Kiana recognizing the twinges and pangs in her chest at the memory of the Hero, and given she's presented as a single-minded warrior who cares for nothing but contests of strength, that's a clear indicator that something that can compete with that obsession now exists, and it's the first thing we see that draws Kiana's attention that isn't a pure love of fighting.
And to that end, we need the flashback to show Reva in combat, to portray just how strong she is. Likewise, we need the flashback of Reva with Cecilia, to show that she is more rounded than Kiana, while being set up as her counterpart. Two rivals, one single-minded and one with varied goals and reasons to fight, who has a soft side when it comes to "maidens" like Cecilia and for earthly pleasures like baked goods. This contrasts the two, and is underpinned by Kiana taking partiuclar interest in Reva, as I stated before.
We don't get any of that without a flashback, and the only way I can immediately think of to otherwise establish Reva's character would be Cecilia having a conversation with Kiana, which would arguably be just as bad of a pacing decision: multiple pages of talking heads spouting exposition is the most literal "tell not show" of storywriting possible.
But this isn't "hammering" that Kiana is battle-obsessed; it's setting up a path forward for her character and for Cecilia to find common ground with her. In that light, Reva's important, and we need her character established in a way that gives a rounded image of who she is/was. Maybe it's a matter of subjective taste, but I'd rather a flashback than several pages of text-heavy exposition from otherwise static characters standing in a room talking at one another.
I'm not sure what you mean by this being a 'twist', though. I was using the previous chapters building on Milfina's character, and Lapience's for that matter, to show that more of the same could be expected when it comes to Kiana. That's me citing the previous characterization to indicate that Kiana will likewise not be as she was initially presented, not claiming that it is or that it needs to be continuously reinforced.
