Gone. Not coming back.
The problem there is that Shane is rather … dense.
Sometimes I feel like the story has reviewed itself for me already. :V
Anyway, you are determined to keep pushing the boundaries of that T rating, huh? When you've got Espeon snorting stardust, you've probably passed that point, honestly. Back to the point, I open with that because it feels appropriate; these couple of chapters push a lot of characters to their lowest ebb in a while, I think, and that forces them to have quite a few conversations that have been a very long time coming. To finally get that payoff is pretty satisfying, I have to say. You've got Gallian finally starting to talk instead of yelling and trying to beat people up; Tessa challenging him over his blatant assholery (like, I know why he did it, but that doesn't excuse that he did it); Shane putting away his dream of being a hero and in the process finally actually becoming the stuff of which heroes are made. The fact that it's taken them all so long to figure out things like 'Gallian has an issue with lucario' is kind of telling; it's a good thing they have someone in Decidueye who's a bit older and wiser and can help them towards these conclusions.
Shane's especially impressive here, I think. He's come so far; he actually wants to be proven wrong now, and he wishes not for glory but for peace. There's a lovely irony to the fact that in the moment where he at last puts aside the goal of being a PMD protagonist, he becomes one in more ways than he knows: yes, there's the whole thing about disappearing, which is of course traditional for a PMD protagonist, but there's also the fact that the main characters of those games tend to be reserved, aware of their limitations, and essentially kind-hearted, and just now, Shane is actually starting to become these things.
Moving on, I wonder if his blasé attitude to his evolution has to do with already having undergone a way more dramatic change in shape before? He does have that moment of excess energy, but other than that he pretty much just doesn't care, which made me consider the fact that that first transformation must have been much more traumatic than this one.
Something that these more conversation-heavy chapters bring to the fore is an occasional woodenness to the way characters interact with and react to one another. Like this:
Silvally's words irritated Espeon.
Gallian was taken aback by this.
It kind of reads like stage directions rather than the actual action itself, you know? You could have something like 'Espeon's tail twitched in irritation' or whatever, and that would make these exchanges feel much more lively.
There's also an odd moment during the part where Shane is reliving one of Solgaleo's memories that looks to me like you rearranged part of the story but left a bit behind by accident. After he realises he's in Solgaleo's memory, he looks at his reflection and is surprised to see that he isn't a ninetales, which strikes me as kind of backwards. Were those bits the other way around before, by any chance?
This time I only have one typo for you:
his thoughts trailed off as he looked into Suicune's soft eyes.
'His' needs to be capitalised here.
Yeah! Really nicely done. Things are looking positive for Team Radiance as people, even if their prospects as fighters against an overwhelming force are a little bleak; they've got old friends and new, all kinds of people banding together to join the push against Prisma, and that's a great place to leave off here. I'm looking forward to finding out what you have planned for the next leg of their journey.