Himemiya's Onihime-sama

The bullying is yet to cease, and so, Yuuka comes home crying one day, to be comforted by Ginka. The family express their concerns, especially after it appears Teika and Hyouka are ready to do some serious about the situation. The next day, Yuuka is confronted by a teenage girl - her biological sister, Senko, who has come to take her younger sister back. The truth regarding Yuuka's previous family is revealed - her family traditionally tortures the youngest daughter - Yuuka - for being a demon. Before the situation gets out of hand, Ginka appears, and apparently knows Senko. Night comes, and the bullies are at it again, this time aided by Senko, who is madder than ever before, claiming she needs to be saved too. Ginka's second arrival spurs this, as Senko wakes up in the Midarezaki household. Kyouka threatens to kill Senko for being an enemy of the family, but Ouka jumps in and pulls her away.