Horatio Kojas is a character from the mecha anime and light novel series Knight's & Magic, serving as the primary antagonist during the series' final story arc. He hails from the Kingdom of Jarrowdek, a nation that serves as the main opposing force to the protagonists' home country of Kuschpercha. Physically, he is depicted as a man with black hair cut to neck-length and distinctive purple eyes.

Horatio is a gifted and ambitious engineer who comes from a lineage of technicians, utilizing his family's secret or proprietary technologies to achieve his goals. His defining trait as a character is his role as a rival inventor to the protagonist, Ernesti Echevarria. Rather than being a warrior or a political leader, Horatio represents the power of technological innovation on the battlefield. He is highly intelligent, possessing a tactical mind capable of matching Ernesti's own genius. The narrative frames him as a "mad scientist" archetype, an egotistical enthusiast who is deeply confident in his own abilities and convinced that he is the superior inventor. He is driven by a desire to prove his technological superiority over Ernesti, seeing the young prodigy not just as an enemy soldier but as a direct rival in the field of mecha design and magical engineering.

In the story, Horatio secures the cooperation of the Jarrowdek royal family by capitalizing on their desire for revenge, allowing him to implement his ambitious and bold plans. His primary contribution to the conflict is the development of a revolutionary aerial warship for Jarrowdek. The most notable of his creations is the Vyvern, a gigantic airship built in the shape of a flying dragon, which represents a significant leap forward in the setting's naval technology. Prior to this, he was also responsible for completing the Levitate Ship, a testament to his engineering prowess. Throughout the climax of the series, he directly confronts Ernesti and his Silver Phoenix Knight Order. In combat, Horatio proves his strategic value by devising effective countermeasures against Ernesti's otherwise dominant Silhouette Knight, the Ikaruga. For example, he developed a method to neutralize the Ikaruga's jet propulsion systems, temporarily negating its primary advantage in speed and mobility. Additionally, he created a prototype device known as the Blood Grail, which further upgraded the already powerful Ether Supplier, a piece of magical technology that enhances a Silhouette Knight's capabilities. Through these inventions, Horatio successfully raises the stakes of the conflict, forcing the protagonists to think more creatively in order to overcome the technological edge he has provided to Jarrowdek.