Roberto Luís is the posthumously born son of Germán Luís and Ximena Coronado, conceived before Germán's death during *The Carved Seal of Flames*. He inherited the name "Roberto Luís" after his father discarded it. Roberto is the paternal half-brother of León Luís and the maternal second cousin of Prince Alfonso San Valiante.

Raised in Valiante by his mother Ximena following Germán's demise, Roberto came under the guardianship and training of León by age three during *Divine Flame*. León prepared him to inherit the title of Zoro the Shadow Cutting Knight and its equipment, including the Zoro Daggers and Zoro Armor. Despite intensive dual-sword combat drills, Roberto displayed a naturally soft and sensitive temperament, frequently becoming tearful during training. His gentle nature caused concern for Ximena and Alfonso regarding his suitability as a Makai Knight, but León persisted, determined to prevent Roberto from repeating his own past errors.

Roberto became pivotal to the conflict in *Divine Flame* when thralls under the command of the fallen Makai Knight Dario Montoya abducted him. Dario intended to sacrifice Roberto to activate Zirkel's Ring, a magical artifact capable of opening a gateway to the Makai world, in collaboration with the Dead Tower Horror Nigra Venus. This prompted a rescue mission involving León, the temporarily resurrected Germán (revived by Garm), Alfonso, and Ema Guzmán, culminating in a confrontation at the lake kingdom of Vazelia.

Physically, Roberto is a young child with yellow/blonde hair and violet eyes. His lineage defines his background: grandson of the deceased Anna Luís and Fernando San Valiante, nephew of Esmeralda San Valiante, and cousin of Alfonso. León frequently emphasizes Roberto's connection to Germán, stressing the importance of him meeting his father's legacy as Zoro.