Otto II (d. 1147), Count of Duras, son of Giselbert II, Count of Duras, and his wife Gertrud.
Otto married Berthe of Valenciennes, daughter of Yolande of Guelders, daughter of Gerard I, Count of Guelders. Yolande was first married to Baldwin III, Count of Hainaut, and was mother to Baldwin IV, Count of Hainaut. Interestingly, Yolande was granddaughter of Albert III, Count of Namur, a family with strong relations with Otto’s father.
Otto and Berthe had one child:
Julienne (d. 1164), married first Godefroi, Count of Montage, Duras and Clermont, and second Enguerrand d’Orbais.
Wolters identifies Julienne as Otto's sister, but this seems unlikely given the succession of the Counts of Duras. Julienne and Godefroi had five children, the eldest of which was Gilles, Count of Montaigu, Duras, and Clermont, who married Lauretta, daughter of Louis I, Count of Looz. Their third son Conan was also Count of Duras.