"She had died saving everyone..." they said, "That apocalypse monster was put down we're all safe..." they said, "The teeth of the maw were broken, the mouth sewn shut" the voice said.
Jen used to have a happy family... Mommy was a powerful magical girl who was often on the front lines against the stronger forces of demons and monsters, and daddy was an adept businessman bringing home plenty of money and was able to help Mommy rest quite a lot. Then when Mommy was away the demons came for her family, and while help came... Jen teared up as she remembered her daddy running into the open to distract the demons... it was enough to save Jen...
There were talks of some family for Jen to stay with. The fortune left for her would be frozen till she came of age, and currently there was a government worker who worked with battle magical girls... Every now and then there had to be someone to break the bad news. The worker was in the kitchen making a nice soup as Jen stared at her mother's magic core. She fell but the core was still intact. Everyone agreeing that the body was in no shape to be shown off, but the core of concentrated magic that may as well be her soul would be worthy of being shown off at the funeral.
"I can reunite you with your mother, she will never leave you." the voice said. Jen was young and susceptible to deception. She just wanted her mom... She accepted the voice, and the voice accepted her. "Eat it, and you will be together." Jen held the magic core which was the
size of a plum, and put it in her mouth. The voice modified Jen's body a little allowing the magic core to be swallowed whole, and then there was a flash of light.
The government worker, a battle magical girl in her own right that mostly fought petty criminals, saw the flash of light and set the soup to stew a bit. That seemed like the flash of a magical girl transformation, did the daughter awaken to her power? They did some tests though and she had little aptitude to- She saw the brilliant blue eyes of the magical girl who had fallen in battle that day. Brimming with power there was something in those eyes.
The voice was shouting in Jen's mind "She will take mommy away! End her quick! Stay with Mommy! You have the power!" The voice was twisting Jen's mind, and with ease Jen ended the government worker. "Her core!" the voice shouted "To stay with Mommy you'll need more power!" Drunk on power Jen ripped through the body of the government worker bare handed and found the core. A simple swallow later and the voice knew she had developed the taste. Maybe not of human flesh yet, but of the magic of magical girls. To taste their essence, and incorporate them into herself.
There was a sign of a struggle, magical girl core and daughter gone missing, but the government worker was off the hook as they had seemed to have done their best. So the government worker was able to go back to their apartment, and lock the door, and fall in bed as she morphed back into a little girl... a bit corrupted. Her mouth widened seemingly painfully, her hands morphed more into claws and there were slits on the palms. Jen felt something inside her hands and tried moving them. The slits opened up showing more teeth and tongues. Jen could feel her mortal flesh being shaped as more maws appeared over her body.
The monster he body had defeated was known as "the maw" A monster that seemingly was made of mouths that constantly ate and sucked away at life and magic away without abandon. The spirit was all that was left over the body, and sensed the susceptibility of a small magical girl with a lot of magical potential but no talent. Perfect for his possession, corruption, and revenge. Jen was now the conduit for the maw as she would now need to eat and eat. Not just to stay with "mommy" but to also get the strength needed to stay alive... and maybe continue to eat and eat... and eat