|Spoiler Alert: This page contains spoilers. Read at your own risk.|
|Full Name||Juumonji Katsuto|
|School|| First High School |
|Weapons & Equipments|
|Equipment/s||General Mobile Casting Assistant Device (CAD)|
|Voiced By||Junichi Suwabe (Anime)|
|Novel||Volume 2, Chapter 6|
|Manga||Volume 1, Chapter 3|
|Anime||Episode 4, Enrollment Chapter IV|
Appearance and Personality
Katsuto is described as a rather big man, 185 cm in height with a thick chest and broad shoulders, with rippling muscles that are easily recognizable even under a uniform. He also gives off an incredibly heavy sense of presence.
Katsuto is usually passive, only commenting when necessary. However, he is honorable and dependable and has a very strong sense of responsibility, worthy to be the Juumonji family's successor.
Tatsuya had once thought that Katsuto has a forceful personality, someone who doesn't seem like the type who would bar his subordinates from fighting. Like Mari and Mayumi, he also doesn't discriminate against Weeds, which is evident when he supported Tatsuya to be one of the auxiliaries for the Nine Schools Competition and when he reasoned with Tatsuya to accept and represent their school for Monolith Code.
|“||Katsuto, he who returned the cheers of victory, understood the value of that power and how to utilize it. He carried the majesty of a monarch.||”|
—Tatsuya, Volume 4, Chapter 13
Katsuto is the eldest son of the Juumonji Family, and in the future he will become the clan head of the Juumonji. He studied at First High School
Katsuto was a member of the Cross-Field Club before becoming the Leader of the Club Management Group. Even after he left the club, Katsuto continued to use the second club room privately, this was an open secret. 
Phalanx (鐵壁) is a Move-Type Defensive Magic that isn't simply a sustained magic barrier, but a barrier that continuously refreshes itself. This is similar to a dense formation of heavy infantry that marches as one to increase the group's defensive power and then translates that power into offense.
Even if the initial barrier falters, the one behind would simply replace it, to be continued to add infinitude. The barriers are in constant motion within set boundaries, not necessarily in front of oneself, but rather dozens of barriers can be sent crashing at high speeds into the enemy. It is impermeable to gas and can resist temperatures in excess of 20,000°C. (Note that the temperature of a "small" conventional nuclear blast, such as the one exploded over Nagasaki, is more that 1,000,000°C at the epicenter. Modern nuclear weapons produce temperatures in the tens of millions of degrees at their epicenter.)
- Multiple barriers being erected simultaneously.
- The offensive barrier which possesses the sole function of being impermeable to all attacks can even be spread out within another person's magic. The magic barrier that sets matter as its target possesses the interference strength that simply disallows any other magic to exist.
- Although there are disadvantages in that the firing range is limited and it can only be used against existing phenomena, this magic that combines anti-personnel, anti-object, and anti-magic properties has powerful applications at short distances in group combat.
- This magic inherited the name from the ancient Greeks' formation and displays defensive prowess and suffocating pressure worthy of its lofty name.
It is an Area Of Effect Magic that ignores solids, fluids, and gases and creates a force field reversing motion vectors.
The Juumonji Family took the next step to hone their natural talents in spatial awareness. Their ability to wield multiple types of Area of Effect defensive magic has earned them the title Iron Wall. With his skills he is able to cast extremely difficult defensive Area of Effect Magics from 400 meters out. Thanks to his mastery of space manipulation and his sensitivity to changes in spatial distribution, he can read the "meaning" like Tatsuya with his Elemental Sight.