Genpachiro Otta (追田 現八郎 Otta Genpachirō) is a foul-mouthed, but reliable lieutenant of the First Division.
Five years prior to the series, Genpachiro was a veteran policeman alongside his mentor, Shingo Tachibana. When a vigilante named Judge attacked random people, Genpachiro and Shingo tried to track him. Judge seemingly committed suicide with his identity "revealed" as Toma Okajima. Genpachiro and Shingo didn't buy for this trick, given that Toma had removed Judge's button and his sister, Aki knew her brother wouldn't commit such act. They searched for Toma's evidence at the same spot he died but no avail. In the end, his mentor retired two years later and keep tracking Judge while Genpachiro continued his work as a policeman and successfully ranked up to the Lieutenant rank.
During his first assignment to the team, Genpachiro tried to fit himself, believing the whole team was a nuisance. However, after witnessing the Roidmudes and Drive (despite being mash-ups of glimpses), he fully trusts the team and tried to get the higher police forces to cooperate with the Unit. However, his efforts eventually in vain as they never believed in him, thinking that he had became more childish. Nonetheless, he tried his best to apprehend the Roidmudes with his work eased from the help of Rinna's backpack.
Resurfaced Of Judge's Case
Sometime later, Judge's case resurfaced but this time, he was able to incapacitate a larger criminal group than attacking one people. Hearing the case again, Gen took it on his own, and swears to quit as a policeman if he fails. Genpachiro and Shinnosuke tracked his target, Tenkawa Angel Real Estate and the vigilante appeared, but in the form of a Roidmude. Nonetheless, he incapacitated them and leaved. After receiving his fixed backpack from Rinna, Genpachiro and his teammates tried to take him down again when Judge attacked Black Candle members but fainted with only a simple kendo technique after realised something. Regaining consciousness, Gen approached to Judge and unmasked his identity as his mentor, Tachibana before getting away with smokescreens. Why is Lt. Otta Following That Guy?
After Shinnosuke and Kiriko managed to get the human Judge's identity as So Utsuki, the three decided to get the evidence again and mobilize before Utsuki made his move at 4 pm. Just as Genpachiro is about to fell in despair, the Shift Car Deco Traveller cheers him up. An idea hits Gen where he and Kiriko use Judge's hunting method to trap him with Shinnnosuke brought along So's button that Toma ripped. After Judge Roidmude's defeat, Genpachiro hesitantly tried to arrest his former mentor for allying with a Roidmude but Shinnosuke explains that Tachibana's only crime of giving in to his torment has already been dealt with, and advises him to tell Akie that her brother has been proven innocent. Tachibana commends Gen for having such a good team to work with.
Discovery Of The Kamen Riders' Identities
After the case where Hajime Taga bonded with Roidmude 007 to form Sword Roidmude, Genpachiro finally witnessed his teammate Shinnosuke Tomari transforming into Kamen Rider Drive after being forced to save Hayase from Hajime. After the fight ended, he as well discover Kiriko's little brother Go being Kamen Rider Mach and in the end both him and Kyu were brought to the Drive Pit for the first time. As of this event, all of the First Division started to believe in his words as they deeply regret for laughing at him previously when Gunman Roidmude's case was brought up. Why Has a New Battle Started?
After the elimination of the Roidmude threat, Genpachiro was promoted to inspector and later became the new chief of the First Division.
Chou Movie War Genesis
Gen attended the wedding of Shinnosuke and Kiriko along with the rest of the former Special Investigation Unit as well as the Mysterious Phenomenon Institute team.
Kamen Rider Drive: Final Stage
In the stage show, Genpachiro became the second user of the Mass Produced Mach Driver, transforming into a Production Model Mach, which he called himself "Kamen Rider Genpachiro" (仮面ライダー現八郎 Kamen Raidā Genpachirō).
After his first assignment to the Special Investigation Unit, he finds the team a burden and mocks them by calling it an "Occult Club". Even if that's the case, he gets along with Shinnosuke and loves children something which he didn't want anybody to be aware of. Due to this, he always shown partnering with Shinnosuke in most of his missions.
Like must higher-up police officers, at first he believes in anything he can see. Unfortunately for him and to the annoyance of everyone, this doesn't include the Heavy Acceleration effects, even when he is experiencing one, to the point of blatant denial. He eventually grows out of this, starting with the Crush Roidmude incident, as well as seeing glimpses of the Kamen Rider, then reaches the point where he believes that a Roidmude was the culprit of a land shark getting assaulted in his house.
Even if he has a lot of comic relief scenes, but he is also at times helpful and observant of one's problems.
- Heavy Acceleration Reducing Machine - A special backpack created to reduce Heavy Acceleration effects.
- Shift Car Holder - Later replaces the above after Drive's identity became public. Usually holsters Deco Traveller.
- Mach Driver Production Model - Transformation belt (Stage show only)
- Tokujo-ka Key - Transformation key, based on a redesigned Tridoron Key. (Stage show only)