Kamen Rider SD: Strange!? Kumo Otoko

Kamen Rider SD: Strange!? Kumo Otoko (仮面ライダーSD 怪奇!?クモ男) is an based on the Kamen Rider SD manga. It was originally released to video on March 22nd, 1993.

Plot
The OVA begins with the Kamen Rider squad called the Battle Riders, consisting of Black RX, Rider 1, and ZX destroying a GranShocker soldier factory, after which Rider 1 decides to speed around the race track whilst Black RX and ZX gamble. After being beat up by ZX for welching on his losses, Black RX reveals he has fallen in love with Michiru, an instructor at a local Sportsclub.

Rider 1, Tachibana and ZX decide to help Black RX win Michiru over. After ZX's plan goes completely wrong, Michiru is kidnapped by Kumo Otoko. Shortly afterwards, Black RX is ordered to come alone to a cave to retrieve her from GranShocker. Defying Rider 1 and ZX's advice, Black RX goes to save Michiru, only to find she's been brainwashed and ordered to kill him. Black RX is beaten senseless by Kumo and Michiru and is helpless to retaliate.

After Rider 1 and ZX show up to help, Tachibana calls in V3's squad for assistance. The Mechanic Riders, V3, X, and Super-1 make short work of GranShocker's troops while Rider 1 and ZX assist Black RX. Super-1 is able to break the mind control over Michiru, after which Black RX destroys Kumo-Otoko.

Afterwards, Michiru is awoken by V3, who instantly becomes smitten with her. V3 and Michiru ride off into the sunset, while Black RX is left behind to cry over his loss, which he quickly forgets after triumphantly burying the defeated General Jak in the sand.

Movie Background
The Kamen Riders do not appear to have human forms in this movie, and remain in their transformed states throughout the entire movie. (A flashback indicates that BLACK RX and Shadowmoon have both been Kamen Riders ever since they were children, negating the existence of Kamen Rider BLACK.) The shapes of their helmets change to show their emotion; their mouthplates move while they are talking. Akiji Kobayashi was the only Kamen Rider live action veteran to voice his character, Tachibana Tobei; Hiroshi Fujioka and the other past actors did not reprise their roles for this animated short.

Kamen Rider Squad

 * Kamen Rider Black RX: The newest Kamen Rider and star of this animated short. Black RX is still new to being a Kamen Rider and often leaps before he looks. In the movie, he has fallen in love with an instructor at a local sports club, which GranShocker kidnaps in a plan to destroy the Kamen Riders once and for all. He has been paired up in a team with Kamen Rider #1 and Kamen Rider ZX, the latter of which has taken a liking to teasing the young Rider. His finishing move is slashing his enemies with his Revolcane sword. He rides on a modified version of the Acrobatter motorcycle.
 * Kamen Rider 1: The original and most experienced Kamen Rider, whom everyone simply refers to as "sempai." He is often found racing around on his Cyclone motorcycle trying to beat his track records, while at the same time putting up with the daily annoyances of Black RX and ZX. He often lectures the other Riders on focusing on their training. He is the team leader of his squad, which includes Black RX and ZX. His finishing move is the "Rider Kick" and appears in the movie in his silver-gloved form. He rides on a modified version of the New-Cyclone motorcycle.
 * ZX: A relatively new Kamen Rider. In a sharp contrast to his original television counterpart, the animated version of ZX is very lighthearted, and quite eccentric. He has taken a liking to messing with Black RX, as well as gambling with him for money he doesn't have. His fighting style is similar to a ninja, including the art of instant disguise (he turns into a gangster and a female tennis player) and high agility. He finds Black RX's problem with love very hilarious, although he does his best to help, which only makes things worse. His team squad includes Black RX and Rider 1. He Rides on a modified version of the Helldiver Motorcycle.
 * V3: A seasoned Kamen Rider, V3 is highly respected among his fellow Riders, and for good reason. He is a highly skilled person, in both fighting and life. When he first appears in the movie, he is relaxing at a hot spring along with his squad. He ends up falling in love with the same girl whom Black RX has a crush on, and ultimately steals his gift for her to win her over, much to the disappointment of Black RX. He is the team leader of his squad, which includes X and Super-1. He rides on a modified version of the Hurricane motorcycle.
 * X: One of the alumni Riders. He was originally built for aquatic combat, and carries a multipurpose weapon called Ridol. He is fairly in the background for this animated short. He is on the same squad as V3 and Super-1. He rides on a modified version of the Cruiser motorcycle.
 * Super-1: A newer Kamen Rider made for outer space exploration purposes. His multiple hands ability is used in the movie when he uses the Blue Lightning hand against Kumo-Otoko. Aside from that, he mostly spends the movie in the background along with Kamen Rider X. He rides around in the V-jet.
 * SkyRider: Rather than travelling with a squad, this Kamen Rider is apparently on his own. With his ability to fly, he serves as a "lookout" for the other Kamen Riders, often carrying around a video camera and broadcasting it on "Sky Rider Television." He is last seen being knocked off of a football goal by a stray football during GranShocker's attack on a sports arena. Skyrider lacks a motorcycle in the movie, riding with Amazon on his Jungler.
 * Riderman: A Kamen Rider in name only, Riderman is the only Rider whom actually has a face underneath his helmet. He has the Power-Arm equipped through the whole movie, although it seems to function like the rope arm too as demonstrated in the opening. He appears as Black RX is trying to court Hachi-Onna, managing to steal her from Black RX and send him running away in anger. He lacks a motorcycle in the movie, riding with Kamen Rider #2 on his New-Cyclone.
 * Kamen Rider 2: The second Kamen Rider, Rider 2 is apparently on vacation in the tropics with his squad, only making a brief cameo towards the end of the movie. He is on the same squad as Amazon and Stronger. He appears in his red gloves form. He rides on his New-Cyclone motorcycle.
 * Amazon: A relatively unorthodox Kamen Rider, Amazon is apparently on vacation in the tropics with his squad, only making a brief cameo towards the end of the movie. He is on the same squad as Rider 2 and Stronger. He rides on his Jungler motorcycle.
 * Stronger: An electricity-based Kamen Rider, Stronger is apparently on vacation in the tropics with his squad, only making a brief cameo towards the end of the movie. (He is swimming in a pool, yet not frying anyone.) He is the leader of his squad, which includes Rider 2 and Amazon. He rides on his Kabutoro motorcycle.
 * Tachibana Tobei: The mentor and racing coach of the Kamen Riders, he is apparently living with them at the same time. He spends his time trying to instruct the Riders throughout the movie, although they do not seem to be listening. He is the only human in the whole movie who actually matches the Riders in height, while everyone else is normal-sized.
 * Michiru: A sports-club instructor and the source of Black RX's lovesickness. She is abducted and later brainwashed by GranShocker, causing her to fight against the Riders. She is later saved by Black RX, but winds up falling in love with V3.

GranShocker

 * General Jark: The current general of GranShocker. In a stark contrast from his television counterpart, he is short-tempered and quick to anger, often going so far as to blow up his own headquarters simply to destroy a cockroach. He is defeated in the end of the movie after blowing up his headquarters for the third time.
 * Ambassador Hell: He was among the meeting with the Great Leader. Unlike his television counterpart, his helmet has horns on the side right eye is cybernetic.
 * Ambassador Darkness : He was among the meeting with the Great Leader. Ulike his tv counterpart, his left is is cybernetic.
 * General Shadow: He was among the meeting with the Great Leader. This version wears a black top hat.
 * Apollo Geist: He was among the meeting with the Great Leader.
 * Doktor G: He was among the meeting with the Great Leader.
 * Ten-Faced Demon Gorgos: He was among the meeting with the Great Leader. This wear appears to have wings.
 * The Great Leader: The apparent controlling force of every Kamen Rider villain since the original series. He appears in SD as an overly large body sitting atop a throne with a booming voice.
 * GranShocker Soldiers: The soldiers of GranShocker wear blue and yellow uniforms, although they appear to pose little threat against the Kamen Riders, and are easily beaten. They all make high-pitched squeals for dialogue.
 * Shadow Moon: The brother of Black RX and apparently a Kamen Rider himself. This version of Shadow Moon tries his best to be evil, but falls short of his own expectations. He is armed with the Satan Saber and an unknown motorcycle (possibly a Road Sector modification). He is constantly teased by Black RX, whom refers to him as "Sunshine Moon."
 * Kumo-Otoko: The very first kajin to ever appear in Kamen Rider is the main villain whom RX is fighting against in this animated short. He kidnaps Michiru and brainwashes her, and sets a trap for Black RX. He is weakened by the other Riders just in time for Black RX to destroy him.

Other Characters

 * A assortment of secondary Kamen Rider characters appear throughout Kamen Rider SD, including Electro-Wave Human Tackle (Stronger's partner) and Kamen Rider Shin. Many past Monsters from several series appear as well.

Home video releases
Distinctly, ''Kamen Rider SD: Strange!? Kumo Otoko'' has never released been released to DVD.
 * Kamen Rider SD: Strange!? Kumo Otoko was originally released on VHS video on March 22nd 1993.
 * Remastered in high definition, the OVA SD was included as a bonus feature of the Kamen Rider: Shin · ZO · J Blu-ray Disc BOX; compiling the three live-action Kamen Rider Series films of the 1990s, it was released on December 24th 2015.