I edge away from Sabina into other things, then get drawn back. There are just so many possibilities!
Lucilla, of course, was meant to be a bit player whom we would glimpse in passing. She was the trigger to push Sabina over the edge, and we had to see her crucifixion - her sixth one - through Sabina's eyes. Lucilla had to be extraordinary, her story so over-the-top that it would be barely possible. I wanted it to overpower Sabina, actually overload her crux obsession so that it dominated and completely controlled her.
So yes, I continue to think about how I could approach Lucilla's full story. I think it should begin with a flashback to her trial, where the magistrate delivers her sentence. For Lucilla, this is beyond horrific - a sentence to an agonizing hell for what is going to seem like eternity, when she did nothing to deserve punishment. But everyone will turn to Balbus, the carnifex, and ask him, can you do it? It's going to be a challenge to him to put Lucilla up on a cross twelve times. And maybe that story ends with Lucilla's first crucifixion and coming to her senses after days of agony to find herself recuperating in a prison cell and realizing that she's going to suffer like that again as soon as she has recovered enough.
So it could be done as several stories, not twelve of them but maybe three or four, ending with her final crucifixion. All of which would be under the umbrella of The Serpent's Eye universe. And there could be other stories from other characters, such as Verina, the prostitute whose mother died on a cross. Or maybe Julia Lepida, who has to be sure that no one can reveal her secret.