The French's Killer Spy, known as La Pucelle de Tonnerre possessed piercing cold blue eyes, d'Eon's true identity remains mystery, either interpreted as a brilliant diplomat, valiant soldier and dutiful son of mayor Charles or enigmatic, eccentric spy Lia the noblewoman or anything d'Eon wants..

Only few knew the true d'Eon.

d'Eon has a long, white hair and pale white skin that similar to ghost. Wears dark green and red dragoon-inspired shirt with white frill skirt, beneath the skirt wearing dark pale trousers and black military boots. Wearing a black hat with French banner ribbon, feather and blue rose. Sometimes wears iconic Captain Dragoon Uniform or 18th century Frenchman attire depending on mood.

Despite feminine face and appearance, d'Eon's voice actually deep and masculine, also hiding muscular body with battlescars beneath outwardly slender bodyshape.

d'Eon's androgynous, hauntingly beauty is seen feminine outwardly, with masculine personality.

d'Eon is one of best swordsmen and appearance of ghost-like makes d'Eon the greatest killer spy. Using sabre-cane sword when fighting humans, d'Eon partnered with Hjörprimul, the 'Sword-Warrioress' Valkyrie, which fitting for her Einherjar partner d'Éon who bears the title 'La Pucelle de Tonnerre' as Hjörprimul will transform into schiavona sword during völundr, both for slashing and thrusting. She specialized in European swordsmanship including fencing and hema.

d'Eon is the best Secret du Roi agent and getting most of works, yet still threatens to blackmail the king and another members to get what d'Eon wants.

d'Eon is avid feminist, so avoid mentioning anything related to feminism.

(Note: d'Eon is Record of Ragnarok Fan-made Roster Character.)