I can see a lot of potential in this setting, especially in the fluidity of form. A person could, through tremendous effort, transfom themselves into a myriad of fantastical creatures. This by itself could create social divisions between say, a self-made tiger and their largely bovid family, or between a Born-Again dragon and everyone they see as beneath them. Then there is the potential for secretive orders that try to induce change in their member for whatever reason. It's very interesting, and I look forward to where you go with it.

Thank you very much! Yes, you very rightly noticed that there can be very different reactions of society, different groups, and I would very much like to trace them. Yes, fantastical creatures are also possible here, but it seems to me that they are always revealed as a form that needs to be achieved by an incredible overcoming of oneself, and this inevitably leads to some distance of such a person from society.
Thank you for your interest, it inspires me a lot!