A man from south west Wales has gone on trial accused of fathering six children by his own daughter, who he allegedly raped 23 times.
The defendant is also charged with repeatedly raping one of the girls she gave birth to and another of his daughters.
He denies a total of 36 counts of rape, and one count of assault by penetration.
Prosecutor John Hipkin said the victims were "groomed" to have sex.
He told the jury the defendant, who cannot be identified for legal reasons, would act as a "fake mystic" who would send emails telling them what to do.
Mr Hipkin told the jury: "He did what he wanted to his three daughters and achieved this by systematic control, grooming and brain washing.
"Their will was completely overwritten by him.
"He created a false world touched by witchcraft and mysticism.
"He would use a mystic to get them to do sexual acts with him by sending email messages to them.
"That control over them allowed him to gain sexual satisfaction."
The trial at Swansea Crown court is expected to last three weeks.