|Spoiler Alert: This page contains spoilers. Read at your own risk.|
He's the very first male student who approached Shiba Tatsuya on the day after enrollment day, and has since then been his companion and friend.
He is a member of the Mountaineering Club.
Appearance and Personality
Leo possesses Germanic features, chestnut hair, green eyes, and an athletic body. He is also considered good looking and has gathered the interests of a few girls.
He has an easy-going personality and a bright disposition, along with a frank and direct attitude, which often gets him into heated arguments with Chiba Erika. He's also someone who can be easily persuaded, and motivated to do favors. Sometimes, he can be clueless and ignorant in a certain way. He is quite a courageous and a hot-blooded person.
However, as a descendant of a Fortress Series Magician, Leo also carries a deep fear of going insane and dying early, as many of the first generation test subjects did. In an effort to avoid this, Leo tries to follow his impulses, such as roaming at night like his grandfather, who lived a natural life span.
On enrollment day, Leo introduced himself and mentioned a bit of his background. His father is half-Japanese, and his mother is quarter-Japanese. His grandfather was part of Germany's First Type-Burg Folge (Fortress Series), magicians whose physical abilities were augmented through genetic remodeling, and he was one of the few survivors from the first generation.
Leo is the third generation of "First type"-Burg Folge series. According to Ernst Rosen, apart from his grandfather (Georg Ostburg), every other "First type" died in their first generation itself. Therefore, Leo who doesn't show any signs of mental deterioration, and has the "First Type" series is considered a very valuable "subject".
Leo possesses a wild nature that endows him with a swift reaction time and a nose for victory. Furthermore, he possesses inhuman endurance, demonstrated during the final match against Third High School in the Monolith Code event, and in his fight against one of the "Vampires" as a result of his ancestry.
- Magic that stabilizes the relative coordinates of molecules within a narrow area. Leo's Fortifying Magic simultaneously executes the Activation Sequence as well as the design and invocation stages of the Magic Sequence, which spreads out in succession while maintaining a constant state of magic renewal. This process allows his personal CAD and even his own clothes to be hardened to the point where they become similar to a suit of armor in terms of defensive power. Combined with his fists becoming enhanced with Speed and Move Type Magic, Leo can be a truly terrifying force of sheer destruction against his enemies. It is noted that Leo is one of the best (unparalleled) when it comes to Data Fortification. It is also the reason why Tatsuya selected Leo as best suited to use his toy - Mini-Communicator (Weaponized Integrated CAD).
- Panzer (パンツァー German language word that means either tank or armor) is a technique that belongs to the convergence magic system. Regardless of how strong an impact is, the magic fixes the coordinates of the target in order to prevent it from shifting, essentially preventing the target from being broken.
➨ Weaponized-Integrated CAD
- Leo used the Mini-Communicator (Weaponized Integrated CAD), during Monolith Code. It was a prototype designed by Tatsuya that focused on extending the blade portion of the CAD outward to increase its range. It was described by Leo as "a really long sword". He could extend it outwards or fling it like a projectile.
➨ Usuba Kagerō (薄羽蜻蛉)
- The technique relies on Leo's specialty of Fortifying Magic to solidify the flatness of the very thin, transparent, black membrane that is released from the Chiba Family's secret sword "Usuba Kagerō", a weapon made up of a protruding head at the front end that is much wider than the handle and is approximately 10 cm long (from the side, it looked almost like a 50 cm length Latin cross), when activated. 
- This creates an ultra thin blade made up of carbon nanotubes that are woven into an ultra thin plate that is 5 nano-meters thick, making it sharper than any sword or razor, and can easily cut any armor in half.
- Usuba Kagerō is essentially Leo's custom made, powerful finishing strike, resulting from highly intense training in a short period of time with Erika.
- Siegfried(ジークフリート) is a technique that hardens ones own body and is Leo's trump card. Siegfried works directly on the body itself, it doesn't apply to objects and can't stabilize relative coordinates like Panzer. It creates a force field that cancels any external force that is inflicted on the body, it protects against piercing, cutting, striking, pressure, and the majority of chemical and electromagnetic attacks that can't permeate through skin and muscle tissue.
Knuckle-Duster Shaped Thought Operated CAD
It was a "gift" from Rosen Magicraft.