A poet and Gilbert's real father, though posing as Gilbert's uncle. Auguste is an adopted son of the house of Cocteau.

Raped by his elder step-brother in his own youth, he abuses Gilbert—first physically and emotionally and later sexually—at a young age. At first attempting to raise Gilbert to be an "obedient pet," he later works to transform him into a "pure" and "artistic" individual through neglect and manipulation of Gilbert's obsessive love for him. Upon learning of Serge's relationship with Gilbert, he works to separate the pair, refusing to allow his "nephew" to bond with anyone who might potentially care for him. He shows true concern only in his last moments when he realizes that Gilbert has fallen in love with Serge.