Wikipedia
Geniscus
Geniscus is a deity who appears in a sermon of Saint Eligius along with Neptune, Orcus, Minerva and Diana. These are all, the Christian homilist says, " demons" who should not be believed in or invoked. The warning implies cult activity for these deities in the northern parts of Merovingian Gaul into the 7th century.
Geniscus may be a form of reference to the Genius, the Roman tutelary deity; in Gaul, the Genius is often hooded ( Genius Cucullatus) and appears either singly or in a group of three.
In another sermon in the same period, the Geniscus appears in the company of witches ( striae) and other entities in whom "rustics" believe: