It sounds like you're referencing a specific release from SapphireFoxx, a studio known for gender bender, transformation (TF) , and body swap adult comics and animations.
: The siblings and their allies work toward a "Regeneration" spell. This Emerald-blooded magic aims to grow a new, independent body for Christina so she can live her own life apart from Chris, supported by a "Mass Memory Alter" spell to integrate her into society as a third Young sibling. SapphireFoxx.com Core Themes Identity and Personhood It sounds like you're referencing a specific release
Introduction to SapphireFoxx and Different Perspectives a studio known for gender bender
Future Developments and Expectations