Ferdinand serves as head priest of Ehrenfest temple, initially appearing stern and pragmatic while managing temple operations and rituals. He possesses light blue shoulder-length hair, pale golden eyes, and a worn appearance suggesting age beyond his years due to chronic overwork. He wears blue priest robes in the temple and distinct knight armor with a unique blue cape—a prize won from Dunkelfelger during his academy days—for knight duties.

Born under the name "Quinta" at the Adalgisa Villa in the Sovereignty, he is the son of Seradina, a princess of Lanzenave. Lanzenave's tradition demanded the execution of all but the highest-mana son of royal bloodlines. As the child without the most mana, he faced execution but escaped to Ehrenfest with the previous archduke's aid, who renamed him. His mother was executed in his place and transformed into a feystone. In Ehrenfest, he was acknowledged as the archduke's illegitimate son but raised outside the castle due to hostility from his stepmother, Veronica. She subjected him to systematic abuse, including poisoned meals and sabotage by untrustworthy retainers, fostering deep-seated distrust, especially toward women.

Academically, Ferdinand excelled at the Royal Academy, graduating as the top student across knight training, scholarship, and archduke candidacy disciplines. He formed lasting bonds with future retainers like Eckhart and Justus. His strategic brilliance in ditter earned him renown, and he completed most trials to become a Zent candidate before abandoning the process after partially absorbing the Book of Mestionora’s knowledge. After graduation, he briefly served in Ehrenfest’s Knight’s Order until Veronica’s escalating threats forced him to relinquish his noble status and join the temple for safety. His transition included a covert conflict with High Bishop Bezewanst, whom he thwarted in a poisoning attempt.

As head priest, Ferdinand managed administrative duties and mana-intensive rituals, often overworking to the point of relying on rejuvenation potions. His isolation eased when Myne (later Rozemyne) entered the temple as an apprentice shrine maiden. Initially viewing her as a useful asset due to her mana and intellect, their relationship evolved into mutual reliance. He became her primary mentor, teaching her noble etiquette, magic, and political strategy while repeatedly intervening to protect her, such as shielding her from rogue knights during trombe extermination. His pragmatic exterior concealed genuine concern; he expressed envy toward Myne’s familial bonds and occasionally comforted her through physical gestures like hugs during emotional distress, despite his usual aversion to touch.

Ferdinand’s role expanded as a strategist for Ehrenfest’s archducal family. He orchestrated Rozemyne’s adoption into nobility and later her establishment as archduke candidate of Alexandria. Political pressures led to his engagement to her, formalizing their familial tie while aligning with his vow to support his half-brother Sylvester as archduke. During Lanzenave’s invasion, he leveraged his Zent candidacy and royal lineage to outmaneuver adversaries like Gervasio, dismantled the royal family, and ensured future Zent selections followed ancient, nonviolent rituals. He ultimately became Alexandria’s High Priest, balancing temple duties with governance alongside Rozemyne.

Throughout his development, Ferdinand maintained core traits: ruthless pragmatism in conflict, devotion to scholarly research, and a concealed capacity for loyalty and affection toward his inner circle. His journey reflects a reconciliation with his traumatic past through his found family and political legacy.