Ken's actor Sotaro Yasuda is the fourth and most recent Sentai Ranger actor to have been born outside Japan as he was born in the US, making him the third to have been born there, with the first two being Diane Martin from Battle Fever J and Kane Kosugi (Jiraiya) from Ninja Sentai Kakuranger, while the only non-Japanese born Sentai Ranger to have been born outside the States is Ei Hamura (Shoji) from Gosei Sentai Dairanger, as he was born in Argentina.
Dawson Casting: Natsume is intended to be in elementary school, but Sakina Kuwae was in middle school when playing the part.
Making Use of the Twin: In episode 38, the Monster of the Week creates an evil duplicate of Retsu that switches places with him. This doppelganger was played by Manpei Takagi's real-life twin brother Shinpei.
According to leaked production notes, the series was originally going to be a Spiritual Successor to Gosei Sentai Dairanger, with a much greater focus on Chinese mythology, including mecha based around the Eastern Zodiac. Interestingly, many of the rejected elements, such as a black ranger with a snake mecha, were later recycled to make Tensou Sentai Goseiger, accounting for its many Dairanger-esque elements despite their wildly different premises.
Miki Masaki was initially conceived as a single mother with a 5 year old child. This child became a teenage daughter, Natsume, and it was established that Miki had a husband in Lesson 13.
