Whether he feels bad about trying to sacrifice Stella or not (I would guess not), Elias can’t accept Chise leaving him. He wants her back, and wanders aimlessly in search of her. When he kills part of the forest he’s in, Spriggan springs into action and takes him down.
Titania and Oberon show up, willing not just to help him find Chise, but to invite them both to the land of the faeries (always with the ulterior motives). Elias declines that particular offer, but Titania still helps him find Chise.
Titania’s powers reach far and wide, and practically everyone Chise has encountered and/or befriended on her various adventures notices those powers. As for Chise herself, she now finds herself watching a young Joseph’s memories.
Joseph was the son of a witch and gravedigger and much hated by the villagefolk for those qualities. But when he finds Cartaphilus half-buried in the woods, he takes him home out of pity, and resolves to heal his extensive injuries using the skills he no doubt learned from his mom.
Only Cartaphilus never gets better, no matter what treatments Joe tries. He doesn’t get worse either, which means the conditions that would allow Joseph to leave the town he hates so much never materialize. Joe snaps, and decides that drastic measures are the only answer: he “becomes one” with Cartaphilus.
The newly merged individual travels (presumably) to London, collecting body parts from innocents to replace the ones that no longer work, and learns from a mage that the ancient curse he has cannot be lifted.
With that, Chise comes out of it, and Cartaphilus almost immediately tries to rip her arm off, hoping it’s the final piece to the puzzle of ending his suffering. It doesn’t look good for Chise until Titania, Elias, Spriggan, and Ruth arrive in the nick of time to save her.
Renfred and Alice arrive as Cartaphilus unleashes his grotesque menagerie, and a big battle occurs in the small space. Still, Chise is laser-focused on Cartaphilus, and when he creates a portal to escape, she follows him, but not before shooting an angry look at Elias.
Elias and Ruth follow her, and they end up in a foggy London alley with Chise, just as a fleeing Cartaphilus bumps into Mariel, who just happens to be in that very same alley. Mariel, hoping to help in some way, transforms herself into a bull for Chise to ride.
They find Cartaphilus sitting on the same fountain we’ve always seen during the second-cour credits. Can Chise end his suffering, while also saving herself?