That was amazing payoff.

The Goddess truly came off like Jelly's big sis.
I was expecting the Dark Lord would end up friend shaped. The theory about OG Jelly as the Dark Lord is great yet the timing this chapter is too convenient with Goddess setting up a mystery and it immediately having the biggest question 'solved' by Leon. Dark Lord has got to be a lesser force, and as most monsters aren't evil... either we already met the Dark Lord in Berger and he'll be compassionate, or the Dark Lord can be negotiated with or replaced. It'd be a waste to use OG!Jelly in that human-monster unity plotline. The cheesier RPG style is to make Dark Jelly a part of the lategame eldritch Calamity, even if it drags out many friends finding out about the slime in the saint until then.
Knight Martina so far is
okay for a character teased (likely planned) as long as we've known Leon. Her intro was brief so she's hopefully not stuck on this stale (admittedly high-impact) cringe. I'm guessing it'll throttle back. Martina is equally qt as Leon, has a nice ceremonial warrior design for someone odd, yuri (yay)... but damn is she redoing a creepy meme as intro. I'd be insulted if nebulous yuri (read: relatable sapphic-explained awkwardness) wasn't already an established Celestria gag.
... mostly I'm worried about what little we know of Martina vs Celestria and Ange, which is clever bait for two clashes, not a shipping thing given age gap (where Martina hopefully isn't ultra creepy)
- Celestria is probably going to be treated as a doll or auntie's favorite. And rage. I think she's barely younger than Ange, at most a couple years, she's simply short (and never won't be). It's more realistic than elementary school genius in platform heels. Her sapphic gag is probably reserved for Jelly, and Martina seems insensitive for now, but maybe there's something positive about putting the two yuri gag characters together.
- Ange is painfully vulnerable to ego boosts and slights so either way her rotund knight best keep her and Martina apart. This is an impending trainwreck for the vain girl. Good could spiral for the needy girl, and a bad outcome is her peers are fawned on but not her... truly fall-to-darkness tier upsetting.
(or OG!jelly was fine before she hit puberty and went unhinged, they did find that diary? of her potentially talking to a darker entity?)
While it would still be in-style for this story to show us the unhappy reasons OG!Jelly got this way, she's a torturer who effectively tried to end the world. An exception to the rule of relatability would be good before a final boss battle, but she's far gone. Whatever she is. That OG!Jelly face this chapter was the least human by far, hard to explain even with spiritual brain damage. So I think something, Jelly's mistake or an outside force, got a screwed up soul into the body. Goddess did give it a chance before what seems like indirect smiting and soul replacement. Tidy but not mandatory is the true OG dead girl's soul becoming a slime.
We may not find out much about the souls changes from the journals by the evil Jelly, even as they provide other clues. I could imagine that psycho was doing ritual magic to get in touch with the Calamity. And as there seems momentum to carry on, OG!Jelly should be at least a supporting antagonist if not shepherding the cataclysm.