First of all, he's a nignog. A Reynolds probably owned his family. It's not likely to be by blood.
The Reynolds came from Wales. The name comes from the fact they were vassals of the Renault family who were awarded the lands in the Norman conquest. The name basically means property of Renault.
The Renault family in turn are descended from the germanic Reginald family.
They in turn are descended from the seer/wizard of the Viking king Ragin.