The story of the Wittebane brothers from The Owl House reminds me of the story of the Bai brothers from Karakuri Circus both in concept and execution.
The entire plot of each series kickstarts when the older brother abandons the younger brother and everything they had pursued together for years for a foreign woman. The younger brother goes mad afterwards, creates a series of artificial beings in the image of a loved one, acquires immortality through immoral means, and becomes the main antagonist of the series. The main antagonist is a foil to the kid hero and possesses or has possessed another human being at some point.
Each series suggests a more complex and sympathetic side of the main antagonist, only to reduce his character to a crazy villain.
In the case of the Wittebane brothers, at least it was a good thing that Caleb unlearned his community's toxic values and the show is so vague on their story that it gives us no idea of what Evelyn's face looked like.
As for the Bai brothers, Karakuri Circus presents their story in a far more visible, albeit equally misleading, manner. Bai Yin nonsencially developed a contempt for his family business after finding out about Francine's tragic background and made that clear to his younger brother while withholding crucial information about his future wife, who had already been good friends with his younger brother, in a moment of callous selfishness. It was Bai Jin who remembered her love for clowns and entertainers even after his descent to madness.
I can't speak a lot about Dana Terrace as I'm only interested in the Wittebane brothers. As for Kazuhiro Fujita, this same manga creator portrayed Lucille, Angelina, and Shoji in a far more graceful manner, so it wasn't like he didn't know better as a writer.