André Grandier, grandson of the Jarjayes family nanny, joined the household at age eight after his parents' death, raised by his grandmother. He trained alongside Oscar François de Jarjayes in fencing and horsemanship, forging a close bond that transcended their differing social classes. As a commoner on the estate, he performed service duties, primarily as a stable hand tending horses, while his grandmother cautioned him about class boundaries—though his rapport with Oscar permitted casual familiarity.

He harbored deep, unspoken romantic feelings for Oscar, demonstrating loyalty through acts like confronting French Guards who disparaged her. Rescuing Oscar from the thief Bernard Chatelet, André suffered a severe left-eye injury from a whip strike; his vision deteriorated until blindness. His anguish surfaced during Oscar’s suitors' proposals, particularly Victor Girodelle’s, driving him to jealous despair. In one crisis, he initiated a double suicide but stopped upon realizing it betrayed Oscar’s needs.

When revolution erupted, André aligned with the commoners, reflecting lifelong awareness of class oppression. After Oscar reciprocated his feelings, they shared a night as committed partners. Despite blindness, he insisted on fighting beside her. On July 13, 1789, he died shielding her from a stray bullet; Oscar discovered his total blindness only posthumously.

Adaptation variances: The 1979 anime attributes his blindness to a sword injury, depicts concurrent deaths with Oscar during the Bastille storming, and heightens his class conflict. The 2025 movie shows debris injuring him while protecting Oscar in a riot, incorporating songs like "Ravine" to convey his turmoil.

Noted details include his atypical literacy, a brief encounter with a Palais-Royal prostitute at eighteen, narrative hints of a potential future with Rosalie Lamorlière, and evolving character design throughout the series.