@heimdal7 There's a quote I found from George Lucas - describing Darth Vader - that I think actually encapsulates this author's conception of Akatsuki quite well:
"You learn that Darth Vader isn’t this monster. He’s a pathetic individual who made a pact with the Devil and lost. And he’s trapped. He’s a sad, pathetic character, not a big evil monster."
And their fates do suggest at least some of them did regret what they'd done to Shiori (not enough to not do it, admittedly, and not necessarily all of them).
Rachel is the most obvious - Zack considers her to have committed suicide-by-monster (she, a rear guard mage, took off on a solo quest without the actual fighters and predictably got herself killed).
After which, the party's four men had a falling out while exploring some ruins, resulting in two of them killing each other, and a third's body never being found. We'll probably never know for sure if it was the guilt from Shiori (and Rachel)'s fates that drove them apart (unless Shiori ever runs into the fourth, surviving, man). But if Shiori's recollection is accurate (Rachel and two of the men being guilty at abandoning her), the falling out being between the two guys who felt guilt and the two who did not would seem a pretty logical explanation.