A cousin of Perceval in Wolfram’s Parzival, identical to an unnamed lady in Chrétien de Troyes’s Perceval. Her mother, Scoysiane, died giving birth to her, so she was raised by Queen Herzeloyde of Wales (Herselojde), Perceval’s mother. R. S. Loomis thought that her name was an anagram of cusine ("cousin").
While in the forest of Brizljan with her lover, Schionatulander, she found a hound with an extremely long leash. The leash had a story inscribed upon it, which Sigune only partially read before the hound bolted away, dragging the leash with it. Sigune sent Schionatulander after the hound, and he was killed during the quest by Duke Orguelleus of Lalander. Perceval, on his way to Arthur’s court, came across Sigune holding Schionatulander’s body in her arms. She paused from her grief long enough to inform Perceval of his lineage.
Perceval met her again some time later, as he was riding away from the Grail Castle, having failed to cure the Fisher King. She related some history of the Grail Family and Grail Sword, but left his presence in disgust when she found out he had failed to ask the Grail Question. Later, Perceval came across her again after Schionatulander had been entombed. Sigune was living a life of constant sorrow and penance over her dead lover’s grave. Cundrie the Sorceress, the Grail Maiden, brought her food and drink to sustain her. She tried to point Perceval in the direction of the Grail, but he lost the trail.
After several years of this cloistered asceticism, Sigune died hunched over Schionatulander’s tomb. When Perceval found her, he opened the tomb and interred her next to her lover.