He is depicted as an old man, with a staff. He is one of Kurei's Uruha Death Squad members. The ten of them are the ten most powerful soldiers in Kurei's army. As his name suggests, he is a master of Genjutsu, or illusionary techniques. He is by far the 2nd weakest of the Jyushinshu, with Mikoto being the weakest.
Genjuro fits the stereotype of a mad scientist. He has no regard for morality and does as he sees fit to further his goals. He has even stated there is no such being as god in the world. He is also quite lecherous, and has groped Neon in the anime, and has tried to make her his sex slave in the manga as well. Despite all this, he was honorable enough to keep his word and remove the Shikigami madōgu from Menō Sakura when defeated, and sincerely thanked Yanagi when she offered to heal his wounds, appreciating her compassion.
Part in story
He originally battled against Kurei but lost terribly. He battled him again three years later, and was crushed again, at which point Genjuro referred to him as a demon. Kurei, seeing potential in him, made him one of the Uruha members. Genjuro appeared loyal to Kurei, even teaching him the Shadow Replication technique. However, his real purpose was to kill Kurei, and to take his powers. It was later found out that the reason Kurei formed the Uruha squad was to test the member's loyalty to him.
He entered the Ura Buto Satsujin as one of Kurei's Uruha squad. His team consisted of Shiju, Mokuren, and Menō with Genjuro being the leader. He used Menō as a doll with his Madōgu, his staff which can shrink people. Menō had a time limit of 10 minutes to finish the match, otherwise her father would die in a quicksand tube. Recca Hanabishi attempts to attack Genjuro, but Neon's force field stops him.Recca manages to get past her force field, and destroy Genjuro's staff, ensuring that no one dies in the fight. A mad Recca immediately challenges Genjuro to a match. Although Genjuro didn't have his staff, he used a Genjutsu technique to replicate himself and leave Recca unguarded. However, because he hated Kurei, he decided to use psychic surgery to extract Recca's dragons, but it backfired when Setsuna, the most violent of the eight dragons turned on him and destroyed him. Following his defeat, he kept his word to remove the Shikigami madōgu from Menō's body, and although offered by Yanagi to be healed, he turns her down yet thanks her for her compassion. Seeing that he was a traitor to Kurei, Neon killed him.
In the manga, however, Neon ended up killing his Shadow Replication instead, while he escaped. Genjuro sought refuge from Kōran Mori and helped him protect the cloning Kurei, resulting in the creation of Aoi and Renge. Genjuro was put in charge in one of the fortresses of SODOM City, in which he encountered Neon again. He first overwhelmed her with his robots, but got panicked when he saw Domon Ishijima seemingly allying himself with Neon and her sisters. While Genjuro was attempting retreat, however, Neon thwarted his escape and killed him for good using Jishou's blades.
Abilities and Techniques
Enhanced Speed and Reflexes: Genjuro is very agile for his age.
Mugen (夢幻, Dream): A staff used by Genjuro of Uruha Maboroshii that allows its user to turn illusion into reality either shrinking objects (including people) by affecting its cellular structure or also cause the user vanish as if in a dream. Its primary stone has the kanji for 'Illusion' (幻, Maboroshi) written on it.