the Demons plans(heavily flawed)
the entire premise is that a group of hags(witches) made a deal with some demon that the demon could have the first born male of the family.
but this plan is flawed for one major reason
there is no way the demon would know if the daughters would be able to have children or not.
the only other explanation is that the demons can control and make sure but if thats the case they would have had a male child earlier