Onee-chan wa Kushizashikou!? ~Atashi no Kui de Tsuranuite Ageru~

It began with the outrageous declaration of my sister Crea, who suffers from eighth-grader syndrome. Believing herself to be a reincarnation of Vlad the Impaler, she involves both me, her stepbrother, and her real sister Rakia in lewd schemes under the guise of reviving her memories. From impalement on a giant stake to handcuffs and a neck collar, and even a wooden horse! Crea's demands know no bounds. Are my sister's words just delusions or could they be truthful?