One of my favorite little headcanons that I think about a lot:
Imagine Caleb becoming someone trans people come to for at-cost transition care and Essek as someone who goes to trans folks to help them since he moves around.
That’s part of how each of them works to atone and do good in the world after causing so much pain. To see people flourish and get to really live through the spell they developed together. Create a new legacy. Caleb starts a donation fund for materials for those who can’t afford them.
Caleb and Essek work on creating magical lab-grown gems for a cheaper & steady supply with far less exploitation than mining. A side venture that helps fund their other research & charity work. They sell primarily to hospitals & outreach charities using magic to help communities.
They worry about how the spell could be abused in the wrong hands. I can see a scenario where they use it freely but keep how to cast it secret. Or where Caleb takes on apprentices that help him and teach them to respect its power before teaching them the spell. There is a risk, of course, if people like Ludinus get their hands on it. But they need to be guarded against anyway because they always find a way. It’s a risk worth taking for all the people it helps who can live without pain in the body of their choosing.