Stiyl Magnus was assigned to protect Index alongside Kanzaki Kaori, two years before the start of the series. As Index was a living archive of 103,000 forbidden grimoires, his role was to ensure that no one exploited her knowledge while also preventing her from becoming a threat. However, due to the Church’s strict policies, he was led to believe that Index’s memory needed to be erased every year to prevent the grimoires from corrupting her.

Unbeknownst to him, this was a manipulative lie, and when Touma exposes the truth and rescues Index, Stiyl is forced to confront the reality of his actions. Though initially resentful of Touma’s interference, he later begrudgingly acknowledges him, leading to a complicated alliance as they both continue to protect Index from external threats.

As the series progresses, Stiyl becomes one of the more politically involved magicians, dealing with conflicts between Necessarius, Academy City, and various magic cabals. While he remains loyal to the Church, he is willing to defy orders when they conflict with his personal sense of justice, particularly when it comes to Index’s well-being.

Stiyl is a tall magician with striking red hair and sharp, angular features, giving him a distinct and imposing appearance. He has piercing blue eyes and frequently smokes, which has become one of his most recognizable habits.

Despite being a magician, his attire is reminiscent of a priest, consisting of a long black robe with golden crosses embroidered on the sides. He often wears a silver cross necklace, symbolizing his affiliation with the Church of England. His overall aesthetic contrasts sharply with modern Academy City, reinforcing his status as a representative of the Magic Side.

One of his more notable features is the runes he carves into his surroundings, which serve as the foundation of his powerful flame-based magic.

Stiyl Magnus is calm, calculating, and fiercely loyal, possessing a strong sense of duty toward Necessarius and the Church of England. Unlike Touma, who acts purely on instinct and morality, Stiyl takes a more pragmatic approach, understanding the political complexities of the magic world while still trying to uphold his own beliefs.

Despite his cold and serious demeanor, Stiyl is deeply protective of Index, though he rarely expresses it openly. He holds a complicated mix of guilt and devotion toward her, struggling to reconcile his past actions with his current mission to ensure her freedom and safety. This internal conflict often places him at odds with Touma, as he believes Touma’s reckless idealism puts Index in danger yet he cannot deny that Touma has done more for her than he ever could.

Stiyl is also highly intelligent and manipulative, capable of navigating the politics of the Magic Side with tactical precision. While he prefers direct combat, he is not above using deception and intimidation when necessary. Despite this, he maintains a personal code of honor, refusing to sacrifice innocent people for the sake of victory.

Though he appears stoic and detached, he has moments where his true emotions show, particularly when Index is in danger. His hidden depth and moral complexity make him one of the more intriguing figures in the series.

• First Encounter with Kamijou Touma
  Stiyl Magnus is the first magician Touma encounters, serving as the initial antagonist in Toaru Majutsu no Index. Under orders from Necessarius, he attacks Touma to retrieve Index, believing that her memory must be erased to prevent her from succumbing to the grimoires’ influence. However, during their battle, Touma defeats Stiyl using Imagine Breaker, nullifying his fire magic and exposing the truth behind Index’s condition. This revelation forces Stiyl to reevaluate his beliefs, and though he remains loyal to the Church, he begrudgingly acknowledges Touma’s role in protecting Index.

• Later Missions and Conflicts
  Following his initial defeat, Stiyl shifts into a recurring ally, assisting in various conflicts involving Necessarius and the Magic Side. His role expands beyond combat as he becomes a key player in magical politics, engaging in covert operations against rogue magicians and hostile factions. While he remains firmly aligned with the Church, he increasingly questions its morality, especially when its actions threaten Index or innocent bystanders. Throughout the series, Stiyl takes on dangerous assignments, including infiltrating enemy territories and clashing with high-ranking magicians, proving his strategic importance and combat prowess.

• Navigating the Magic and Science Sides
  Though primarily a figure of the Magic Side, Stiyl frequently interacts with Academy City and scientific organizations, often finding himself at odds with both magical and esper factions. While he maintains a professional and cold exterior, his continued involvement in Index’s safety and Touma’s battles suggests that he is not as indifferent as he claims. His knowledge of magical conflicts and his unwavering loyalty to Necessarius make him a significant force in the struggle between the Magic and Science factions, ensuring that he remains a pivotal character throughout the series.