Berengar Leuvaarden was a Nilfgaardian nobleman, who along with Joachim de Wett, Ardal aep Dahy, the Counts of Broinne and d'Arvy and Stefan Skellen, conspired to remove Emhyr var Emreis from the imperial throne and put Morvran Voorhis in his place.
He may be related to Declan Leuvaarden from The Witcher computer game.