Puella Magi Madoka Magica
TotokoTan for Kyubey
(Adorable/baby sounding voice) Kyubey is a genderless extraterrestrial being posing as a familiar who can grant any wish to a certain girl, on the condition that she become a magical girl and fight against witches. When the chosen girl makes a contract with him, he extracts her soul and places it inside a soul gem, reconstructing their body into a shell that is more resilient in order to fight witches. He constantly tries to get Madoka to make a contract with him, as she allegedly possesses great magical potential within her that would allow her to become the most powerful magical girl. He can only be seen or heard by magical girls and those with "magical" potential, and is able to communicate with them telepathically. Kyubey has an unknown but possibly infinite number of bodies; when one is killed, another body appears and devours the destroyed body.
I will grant each of you one wish, any wish you desire.
If magical girls are said to be born from wishes, then witches are creatures born from curses. Magical girls bring hope to the world, witches bring despair. And since they're invisible to humans, they are that much more insidious. Anxiety and mistrust, rage and hatred... They sow the seeds of disaster all over the world.
That's so odd. Most girls accept my offer right away.