Samurai Calibur, also known simply as Calibur, is a grinchy member of the Neon Genesis Junior High Students, a covert group of Hyper Agents who serve as Gridman's Assist Weapons. While posing as a human, this individual acts as a bodyguard for Rikka Takarada. In emergencies, Calibur accesses a transformation into an Assist Weapon form known as the Gridman Calibur. In human form, Calibur stands 182 cm tall and weighs 65 kg, with a characteristically hunched posture. Medium-long black hair partially obscures the face, with some strands sticking up on top, and blue eyes peer out from behind it, complemented by facial stubble. The attire consists of a grey shirt with a loose black tie clipped to it, a black jacket bearing a purplish mark on its left side, black pants, and shoes. Four katana are carried on the back, a reduction from the original five. The personality is quirky and eccentric, marked by social awkwardness and a frequent disregard for social cues and taboos. This manifests in bumping into doors due to the length of the katana and navigating the city in unconventional ways, such as walking on roofs and jumping off staircases. A stutter appears at the beginning of sentences during casual speech but vanishes when focus or seriousness takes over. Calibur rarely explains actions or motives at length. Despite the unsettling appearance and odd behavior, a deeply considerate nature emerges, such as getting tea for Rikka upon learning she cannot have carbonated drinks and listening patiently to her troubles. Compared to fellow Neon Genesis Junior High Students members, Calibur demonstrates a greater interest in redeeming Anti and is slower to resort to aggression. Calibur possesses superhuman physiology, with strength, speed, and resilience far beyond an ordinary human. Capabilities include carrying the entire Gridman Alliance while leaping between buildings, reacting swiftly enough to slice a falling steel beam to protect others, and fighting Anti in human form for an extended duration. As a formidable swordsman, Calibur wields four serrated blades sharp and durable enough to cut through steel and withstand weapons like Anti's circular saw. These blades can combine into two larger swords. Basic computer skills are also present, such as quickly modifying Junk to optimize Gridman, a standard skill among Hyper Agents. When transformation is required, Calibur shouts the Access Code "Gridman Calibur." Consciousness then resides inside a spherical green gem on the weapon's hilt, from which Calibur supports the wielder. The Gridman Calibur can switch between modes depending on the wielder and situation. Its default Blade Mode is a sword with a black handle and yellow pommel, though its body palette can change color to adapt to different wielders. When wielded by Powered Zenon, it becomes an Axe Mode called the Powered Axe. When wielded by Gridknight, its body assumes black and red coloration and is named the Gridknight Calibur. The weapon can fly for short durations and block enemy beams. Toy representations indicate the axe blade can detach, potentially for use as a shield. Signature moves vary by wielder. Gridman employs the Grid Calibur End, entrapping a target in a special dimension before boosting toward it with thrusters for a slicing strike. Gridknight uses a reverse-grip version called the Knight Calibur End. Full-Powered Gridman executes the Grid Full Power Finish, an energized slash delivered after a full charge. In Axe Mode with Powered Zenon, the finisher is the Jumbo Saber Slash, which cleaves the opponent in half with an energized strike. Calibur's history includes arriving in Tsutsujidai and saving a girl named Hime Kuzuki from a falling truck, an act that granted her the ability to see monsters. Calibur gave Hime one of the five original swords, enabling her to transform and fight using his power through a smartphone app called the Samurai Barrier Gear. They later investigated mysterious occurrences together, such as a girl at an arcade and subsequent monster attacks. During main events, Calibur watched over Yuta Hibiki after his appearance with amnesia and witnessed the school burn down from a kaiju attack. A visit to the Junk Shop provided an optimization upgrade for Junk, and Calibur followed the Gridman Alliance to investigate missing people. When Gridman was losing a battle, Calibur transformed into the Gridman Calibur for the first time to assist. Throughout the conflict, Calibur repeatedly interacted with Anti, alternating between combat and attempts to reason with him. After obtaining Anti's phone number, Calibur tried to convince him he was a living being with a heart who did not need to fight Gridman. Upon besting Anti in battle, Calibur asked what Anti would do after defeating Gridman, a question Anti could not answer, leaving him to ponder it. For the final battle, Calibur and the other Neon Genesis Junior High Students used Acceptors to reintegrate into Gridman, allowing him to assume his true form. After mission completion, Calibur departed with Gridman back to the Hyper World. Trivia notes theorize Calibur represents Gridman's memories pertaining to the Gridman Sword, later confirmed as one of Gridman's splintered fragments. The character design and forms contain several references. The initials S.C. match those of Sam Collins from *Superhuman Samurai Syber-Squad*, and the name "SAMurai Calibur" is a tribute. The design was also based on the current appearance of Masaya Obi, the actor who played Naota Sho in the original *Gridman the Hyper Agent*. The purple mark on the coat references the Dinobot Slug from *Transformers Age of Extinction*. The finishing move, Grid Calibur End, uses animation frames from *The Sun Brave Fighbird*. According to voice drama episodes, Calibur claimed to be 33 years old, though the truth is uncertain due to a secretive nature and instructions to cover his identity. A fondness for cats is mentioned, with several cats at home and a stated willingness to adopt abandoned ones.