A judge yesterday said Duncan Begg had committed "crimes of a vile nature".
Begg tormented his victims in the early 1990s while living in Wick - including indecently assaulting one when she was pregnant.
The 43-year-old appeared at the High Court in Glasgow after being convicted of a total of eight charges.
Begg - who also uses the name Dreghorn - was also placed on the sex offenders list indefinitely.
A trial in Aberdeen previously heard how Begg raped one woman after pouring a bottle of whisky over her.
He also attacked her while she was pregnant and on another occasion when he burned her with a cigarette.
Begg originally went on trial facing a total of 43 charges - including one accusation of having threatened to cook a baby.