De Rais' proclivities were not normal - not really conducive to Henry VIII levels of illegitimate fecundity.
Moreover, almost every noble house in Europe can trace their ancestry to at least the eleventh century, some to the eighth.
There are no historical records tracing any of these houses to de Rais, who died in 1440. Name one European noble descended from de Rais - it should be easily checkable.
De Rais was wealthy because he was awarded lands on account of his military accomplishments, being named Marshal of France. He was not the highest of high borns, and was actually disinherited. His remaining wealth and lands were seized by the King, his brother and his cousins.
Gillis was close enough related to this crowd to be considered an ancestor ~ Ann's the one who ends up in everybody's genealogy ~ and Gillis will be off on a jig on the Montmorency's a mere 20 years earlier. BTW, records generated in France from about 1380 to 1440 are not terribly reliable ~