The following are comments made by the game people in Kitten's preorder artbook, WRITTEN IN ENGLISH, with some story information in them. Don't read if you don't want spoilers, but Sturm, really :(
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"By the time I'd given Ms. Kiyuduki the task of designing Zolgonark, his character had already been decided upon. When I assigned him to her, I hadn't fully explained his connection to Hades in "Riviera," so you can imagine how pleasantly surprised I was when her designs were dead-on with how I'd imagined him..."
-Game Designer Ito
"It was just pure coincidence that I happened to be looking back at "Riviera" designs for inspirations."
-Illustrator Kiyuduki
"When I was working on his illustrations, I had no clue he was supposed to be Hades. All I was concerned with was making sure he'd fit on my paper! *laugh*"
-Illustrator Iwanaga
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"When it comes to Marietta, I decided that since she loses her power in the events of this game, she'd need to look more impressive than her Guardian Angel designs [from "Riviera"]. We just couldn't pass up this chance to give her a divine appearance..."
-Game Designer Ito
"Because I liked Marietta's design in "Riviera" very much, I didn't want to destroy Mr. Iwanaga's original image. Initially, I'd fiven her an archangel feel, but Mr. Ito told me to give her a more grandeur and distinctness for this game, and that's what led to her current design."
-Illustrator Kiyuduki
Rhia says she's always whining about Kitten's timeline contradicting itself or something.