Voorhis was a purely-Nilfgaardian nobleman with considerable influence at the court. Both he and his wife were related to Emperor Emhyr var Emreis, making it easier for their son Morvran Voorhis to eventually seize the throne.
In 1268, Prince Voorhis was considered a candidate for the throne by a conspiracy of Ardal aep Dahy, Joachim de Wett, Count of Broinne, Berengar Leuvaarden, Count D'Arvy, and Stefan Skellen who planned to overthrow Emhyr. Eventually, they decided Morvran would be better because of his young age and dual relation to Emhyr. It's unknown if the prince knew about the conspiracy but he wasn't affected by its fall.
Voorhis was apparently one of very few who, by 1272, knew the secret that Emhyr was the father of the real Ciri. When Voorhis saw new opposition rising, he advised his Imperial relative to consider finding her, marrying her to Morvran, and abdicating the throne to avoid complications.
Personality and traits
He was regarded as a man of iron will who couldn't be controlled.