(this was an idea for a different account I have on different sight But I figured it works for here so it may seem off compared to others) no one know quite who invented the process but people in this world can take a procedure that allows them to shift between their human self and their beast alter at will a beast alter is an anthro animal with 3 times the effectiveness of whatever abilities that animal species has.
The almost always has different gender than there base human but though there very rare kinds called Rarebrites which do share a gender/sex with their original though they have specific conditions(specifics are completely comfortable with initial gender{basically if your disphoric with your birth gender in any small amount it's a definite unlikely you will be a rarebrite, did , no potential use for alternate gendered form(aside from being trans which is converted by the previous condition). age is also varying but it's usually point the opposite younger people turn older while older people turn younger.
Beast alters start out as just their human mind piloting an anthro body but over time with use a process none as de-synergy takes place in which the anthro form will form a soul and mind of their own based on what was done in their form de-synergy takes 2 week minimum but it can take up to a month max after this their clothes will begin to also shift between forms to match their anthro form.
body shape and sexuality are also fluid by matter of beast alters. humans can't exactly choose the anthro they become but they are given some choice via if they choose to right one specific adjective during the injection part of the process. despite having their own soul.
Beastalters cannot have their shifting abilities removed and also do obey the goals set in mind when their human becomes them though how do this goal is there own choice.
You have taken the process(basically being injected with animal spirit energy from a large machine) what is your animal form(name, species, appearance, personality and age)(none of these have to be related your real life self just you in this story what was your optional adjective, what was your reaction to getting them and what do you do with them. (did I handle the transgender thing still a bit mixed on rarebrite thing)