Ducasse was a replicant who functioned as a servant for Hyman and Genevieve Bask.
In 2029, Ducasse poisoned his masters. After removing the husband's eye, Ducasse took it to a man that referred to the eye as a key that would lead to redemption.[1]
Ducasse later killed Ruskin, a Blade Runner assigned to the Bask murder case, tearing his spine out by hand. Upon Yotun's need to extend his life, Ducasse sacrificed some of his own.[2]