As your body changed, a blissful, blue magic swirls around your body, specifically around your waist and your chest, as the magic slowly seeped into your masculine body, it also begun to change your gender. You were no longer a man, but instead a beautiful young woman. Your penis and balls slowly shrank away, sinking deeper into your crotch until it got sucked into your new vagina with a satisfying "Plorp!" sound! The sudden disappearance of your dick, combined with the sudden appearance of a pussy, caused you to blue and let out a soft, girlish moan!~
You instinctively covered your mouth after you let out the moan, and a few moments later, all that strong mana began to flow into your ass and your chest, causing your bust and your butt to grow to and equally large size! Both your boobs and your butt are now the size of beach balls! These, are your mana tanks!
Now that your body was made into a proper physique that can hold all that powerful mana, you would remain in the nude, at least in the security of your apartment, as you rushed over to a mirror and felt your own body in front of it, staring in disbelief at your new body.
"Welcome, Goddess of Magic" A mysterious voice spoke in your mind, a voice that only you could hear, "Welcome to your new life, humans in this word are incapable of using the mana that they hold within their bodies, your new job is to help make people into what they desire the most in life, may it be that they prefer to be the opposite gender, an inanimate object, or even an animal. Your job is to help them become what their true form is. Humans are hidden behind the shackles of their mortal forms, but by releasing them, you can give them immortality by turning them into their true forms."
You only become even more confused as this voice explained to you what your new role in life is, but it's very clear what you must do now...