Cattleya Yvette la Baume le Blanc de la Fontaine, middle sister of Louise de la Vallière, holds a distinct title as head of House La Fontaine granted by her father due to a chronic illness that renders her physically delicate and frequently bedbound. Despite her fragility, she radiates gentle optimism, steadfastly supporting Louise and approving her relationship with Saito despite his common heritage.

A practitioner of earth magic, she commands golems to execute tasks like manipulating a drawbridge during Louise and Saito’s escape. Her secondary water affinity emerges when summoning spirits to heal Saito’s wounds. Though her condition precludes marriage or strenuous exertion, she briefly tutors at Tristain Academy of Magic under Éléonore’s supervision, accompanied by her cherished menagerie of pets.

Framed for ruby theft by Michelle, Cattleya exposes the deception using earth magic and later offers herself as a hostage during an academy siege to safeguard others. Expanded light novel arcs reveal her communing with spirits, aiding Louise’s evasion of familial expectations, and attending Louise and Saito’s wedding.

Her bond with Louise thrives on mutual empathy, anchoring her sister through familial discord. Cattleya discerns Louise’s affection for Saito before Louise herself does, underscoring her emotional acuity. Consistently portrayed across adaptations, she embodies resilient compassion, persistently nurturing others despite her constrained vitality.