Yuusha no Tamago Maou no Shikaku

This is a world where humans and demons have been fighting for ages to protect their respective rights and to seize them. One day, a boy and his father save some girls from a monster and invite them into their home. However, the girls are actually assassins sent by the Demon King to trap the boy, who was born into this world as a hero . Will the boy be able to resist their temptations and overcome the Demon King's schemes? [Edited from DLsite]