Set in the Edo Period of Japan, the series follows a young ninja named Hayate, who is the son of a man who developed a special technique called the "Transformation Jutsu" capable of granting a superhuman form. However, their Ninja clan, the warmongering Blood Wheel Clan, begins using the Transformation Jutsu to spread fear and terror all throughout Japan as part of their campaign to conquer it, going against the peaceful intentions Hayate's father had when creating it. After the Blood Wheel Clan slaughter a village, Hayate is able to convince his initially reluctant father to perform the transformation procedure on him, enabling him to become a birdman ninja known as "Arashi" to defend people from the Blood Wheel Clan. Hayate's father is later murdered by the Blood Wheel Clan when they discover his betrayal, but Hayate himself escapes and teams up with the Iga Clan to fight and keep the Blood Wheel Clan from taking over Japan.
Arashi was made by Toei following the massive success of Kamen Rider and is best described as "Kamen Rider set in Feudal Japan". While not as long-lasting as its sister show, Arashi still enjoyed a great deal of success in its day thanks to its creative combining of the Toku and Jidaigeki genres. Later Kamen Rider shows would go on to pay homage to Arashi in a number of ways, and before Kamen Rider Hibiki was decided to be a Kamen Rider show, one of the ideas for it in its early development stages was to be a revival of Arashi. Henshin Ninja Arashi also received a manga written by Shotaro Ishinomori that ran concurrently with the TV series, and was much Darker and Edgier, depicting Arashi as a ruthless and vengeful Anti-Hero rather than the do-gooder he was in the TV series. A second manga called Henshin Ninja Arashi: Shadow Storm would later be published in 2013, written by Hiroshi Izawa. This manga saw Hayate / Arashi with a personality much more in line with his Toku, and featured him being revived in modern day Japan.
More recently, Henshin Ninja Arashi has become one of the series available on Toei's Tokusatsu World YouTube channel.
- Big Bad: Majin Sai, leader of the Blood Wheel Clan. Later on though he forms a Big Bad Duumvirate with Akuma Doujin of the Western Yokai Army and lets him lead the charge for a bit. And then its revealed Great Demon King Satan was pulling the strings all along.
- Blue Is Heroic: In his regular human form, Hayate predominantly wears blue.
- By the Power of Grayskull!: "Blow Storm, Storm, Storm!"
- Darker and Edgier: The manga to the Toku show. Hayate in particular becomes a much darker Anti-Hero, for the most part concerned just with avenging his father. While the Blood Wheel Clan are still the villains, there are plenty of sympathetic members shown and at times its Hayate who deliberately attacks them rather than the other way around.
- Expy: Arashi is described as "Feudal Kamen Rider" for good reason. He's a masked warrior who fights for justice, is empowered by the same mechanism used by the bad guys and rides a Cool Horse, which can be seen as the medieval equivalent of a Cool Bike. Arashi in turn has inspired the design of Kamen Rider Odin, as well as the design of the Armor of the Ogre in Kamen Rider Hibiki.
- Katanas Are Just Better: Hayate's signature weapon is his Hayakaze katana, which enables his transformation into Arashi and grants him a variety of special abilities.
- Long-Lost Relative: Arashi is aided throughout the series by a mysterious ninja known as Tsukinowa, who eventually turns out to be his long lost brother Fuyute.
- Monster of the Week: The Incarnation Ninjas of the Blood Wheel Clan, later replaced by the Western Yokai brought to Japan by Akuma Doujin.
- Shout-Out: Several in the Kamen Rider franchise, where Arashi is homaged through the designs of some of the Riders. The Makamou in Kamen Rider Hibiki And The Seven Senki are also designed after the Blood Wheel Clan and use a logo that is similar to the Blood Wheel Clan's symbol.
- Tin Tyrant: Majin Sai has his entire body encased in a suit of silvery armor.
- You Killed My Father: Hayate's father is killed by the Blood Wheel Clan in the first episode of the show, spurring on Hayate's quest for revenge.