Kyoko Sakura's Father is a character is in Puella Magi Madoka Magica. He was an unnamed priest of an unknown Christian denomination within Mitakihara, Japan, and was known to be an idealistic man who was constantly troubled by the evil that existed in the world around him. This drove Kyoko's father to preach a doctrine that differed from the canon of the church, stating that religion needed to change to keep up with a changing world. This brought him into conflict with conservative church leaders, and eventually led to his excommunication from the church. Naturally, after his excommunication, most of his congregation left, leaving the Sakura family poor and sometimes only barely having enough to eat.
It was this that drove Kyoko to make a contract with Kyubey in exchange for giving her father the power to make people believe anything he said. Initially, this brought about a reversal of her father's fortunes, resulting in record number of parishioners. Eventually, however, a witch was drawn to Kyoko's father's church. Kyoko managed to vanquish the witch, but in the process, her father discovered that she was a Puella Magi, as well as the fact that Kyoko's wish had essentially robbed people of their free will and given him the power of mind control.
The realization that his daughter was manipulating his parishioners caused Kyoko's father a great deal of anger and despair, and he began drinking heavily. This culminated one night, when he murdered both Kyoko's mother and her younger sister, Momo. It is implied that her father also tried to kill Kyoko, but failed as her Soul Gem remained intact. After committing his murders, Kyoko's father hanged himself, leaving Kyoko the severely psychologically damaged sole survivor. This incident destroyed any sense of her father's ideals in Kyoko, leaving her the cynical, misanthrope shown in the series.