Takahashi Tetsuo, a biology teacher at Shizaki High School, has been fascinated with "demi-humans," beings with characteristics that differ just slightly from humans, since he was in college. He wishes he could have a chance to talk with one, but since the demi-human population is fairly low, he's never even met one. But then the school gains a new math teacher, Satou Sakie... who happens to be a succubus.
Demis are more likely to occur as a 
result of mutation than genetics.
يمكن الحصول على ديمي نتيجةً
.لطفرة ما أكثر من العوامل الوراثيّة
Im Grunde ist der Körperbau
von Werlingen
Es probable que los demis sean resultado
de una mutación y no de la genética.
Es probable que los demis sean resultado
de una mutación y no de la genética.
La naissance d’un demi
Più che di un fattore ereditario,
i Demi sono frutto di una mutazione.
Demis são mais propensos a acontecer 
como resultado de uma mutação genética.
Как правило, деми становятся не из-за
наследственности, а из-за внезапных мутаций.