TV-Series
Description
Weisz Steiner exists in two distinct temporal iterations due to a Chronophage consuming 50 years on Planet Norma. The older version, from X492, is an elderly professor renowned as a "Robotics Genius" for proving "The Brai Theory," though he never published his findings. He possesses a mechanical right arm, replacing the original lost as punishment for stealing money belonging to a loan shark named DJ Zombie during his youth as a thief in Sibir's gang. This incident prompted him to abandon crime, pursue education, and earn his professorial title. He later repaired his friendship with Sibir, though they drifted apart, and remained a lifelong bachelor. His defining act was using his Ether Gear, Machina Maker, to reconfigure the mortally wounded Happy into a machine, saving his life and becoming a benefactor to Rebecca Bluegarden and Happy. Despite past selfishness and thievery, he matured into a caring and knowledgeable figure, advising against his former lifestyle and demonstrating deep understanding of phenomena like the Chronophage. He resides away from Blue Garden and Norma due to personal preference and the latter planet's fragility.

The younger version, from X442, is a selfish thief and former member of Sibir's gang on Norma. His mother died from an unexplained illness during his childhood, profoundly impacting him. After her death, he purchased a used robot that taught him the Machina Maker Ether Gear over three years, though he initially lacked control and accidentally destroyed it. A falling out with Sibir occurred when a pendant left by his mother was stolen; Weisz blamed Sibir, was expelled, and retaliated by stealing a case he believed contained Sibir's money. This case actually held the android E.M. Pino, belonging to DJ Zombie, resulting in Weisz losing his right arm to the loan shark. He encountered Shiki Granbell, Rebecca, and Happy when they arrived on Norma searching for the Professor, causing confusion due to their shared name. Initially motivated by self-interest and profit, he joined Shiki's group after helping them escape Norma aboard the Aqua Wing, which he restructured using Machina Maker. During the escape, he learned from his older self that the Chronophage's attack made them separate entities.

Personality-wise, the young Weisz displayed stubbornness, selfishness, and a focus on stealing valuable items. He took pride in his appearance and was dismayed seeing his elderly counterpart. However, he demonstrated underlying concern for others, partially repairing Happy, showing worry for Rebecca during her kidnapping, rescuing Sister Ivry, and displaying suspicion towards Homura Kogetsu. He possesses a perverted side, often ogling women and planning to put Homura in a bunny girl costume. Traveling with the Edens Zero crew gradually shifts his initially selfish demeanor; he begins showing camaraderie, concern for crew members like Shiki during low moments, and willingness to assist in rescues despite claiming disinterest. He adopts the bombastic superhero persona "Arsenal" when using a powered armor suit constructed with Hermit's help, insisting on in-character heroics. His older self acknowledged their divergent paths.

His primary ability is the Ether Gear Machina Maker, allowing him to control, manipulate, and reconfigure machines. This includes complex tasks like upgrading spacecraft, repairing and modifying androids like Pino and Happy, and creating weapons such as multiple guns from floors or modifying firearms into flamethrowers. The Arsenal Suit significantly enhances this power, enabling techniques like a machine gun, explosive cannon, punch, laser, and blade, though overuse shortens the suit's active time. He achieved Overdrive during a battle with Nasseh, gaining a mechanical appearance, blue hair, enhanced speed, and augmented Machina Maker capabilities. He is also a prodigious engineer and skilled pilot, evidenced by navigating the Aqua Wing through Norma's spacetime wall.

Key relationships define his journey. His deep love for his late mother remains constant across both timelines. He shares a mentor-beneficiary bond with Rebecca and Happy due to saving Happy's life. While initially viewing Shiki as an annoyance, he develops camaraderie with him and the crew. His connection to Pino is practical rather than emotional; he clarifies her creator was the Demon King. His history with Sibir involves friendship, betrayal over the stolen pendant, violent conflict, and eventual reconciliation before drifting apart.