Dragreder

The Unrivaled Dragon Dragreder is a Contract Monster summoned by the titular rider in Kamen Rider Ryuki.

Dragreder, along with every other Mirror Monster, were created from Yui Kanzaki's and Shiro Kanzaki's pictures from when they were younger.

Dragreder initially appeared in Episode 1 and was originally a rampant Mirror Monster that was targeting Shinji. However, Shinji was eventually able to form a contract with it, becoming Kamen Rider Ryuki. Dragreder did not play a very important part in the plot for most of the series and mostly only appeared for Ryuki's Strike Vents and Final Vents or when eating a monster's life force. Despite its role as the main monster of the show, Dragreder acts like any other Mirror Monster: it will listen to Shinji when given definite commands, but will go after him should it run low on life energy. One major difference is that it will sometimes come to Shinji's aid without the need to summon it with an Advent Card.

With the acquirement of the Survive Rekka Advent Card, Ryuki was able to change into Survive Form and hence, Dragreder was able to evolve into a much more powerful form named Dragranzer. With this evolution, Dragranzer was also able to transform into a motorcycle which Ryuki would use to complete his Final Vent. Later on during the end of the war, Dragreder seems to have learned to respect and care for Shinji.

It is unknown what happened to Dragreder after Shinji's death as it did not become rampant. But because Shiro eventually altered time so that the Mirror World never existed, we can also assume the same for Dragreder. However, recent developments show that Dragreder was somehow revived and under the command of Shinji once more without a proper explanation as to how this happened.

Dragreder still supports Ryuki in all of his fights and as part of his Final Vent. A significant battle it took part in though was the final battle between Ryuki and his evil mirror image, Kamen Rider Ryuga. Instead of being summoned, Dragreder came of his own volition, defending Shinji when Ryuga summoned Dragblacker. After helping Shinji finish off both Ryuga and Dragblacker, it evolves into Dragranzer when Shinji assumes Survive Form to take on the Hydragoon horde plaguing the city.

Dragreder is the contract monster of this world's Kamen Rider Ryuki, Shinji Tatsumi, for his participation in the Rider Trials. It never had a chance to appear in the series tribute episodes, and when Shinji used Time Vent, he used too much of its energy, thus Ryuki's Visor can only use a few weak Advent Cards.

To compensate for this, Dragreder became Ryuki's Final Form Ride, allowing Kamen Rider Ryuki to transform into a smaller version of Dragreder.

Dragreder was among the contract monsters that fought Kamen Rider Decade along with their contract holders. It, along with Dragblacker, attacked Decade head on, but were shot down before they could even reach him.

Ryuki assumed Ryuki Survive and got on Dragranzer, among many other Kamen Riders and their Rider Machines, to perform the All Rider Break attack which ended the final battle with Rock Great Leader.

Kamen Rider Decade used an Attack Ride Card which summons Dragreder when he is in his Ryuki Form. In response, Captain Marvelous as GekiRed utilized "Geki Waza! Gun-Gun Bullet!" (激技! 砲砲弾! Geki Waza! Hō Hō Dan!), summoning a manifestation of GekiTiger. They were evenly matched.

Later, in the last stages of the battle with the Shocker-Zangyack Alliance, Dragreder was summoned by Ryuki himself for the Dragon Rider Kick. This, combined with Kamen Rider Blade's Lightning Blast and Decade's Dimensional Kick, was able to defeat Doktor G, revealing him to be Narutaki in disguise.

During the 14 Heisei Kamen Riders' battle against Amadum's monsters in the World within the Magic Stone, when various giant and flying monsters appeared, Ryuki noted that they could handle big enemies too. He proceeded to board Dragreder, fighting alongside the other Riders pulling off their various tricks and destroying several Hydragoons.

During the final showdown between the 15 Heisei Riders and 15 Showa Riders, Ryuki summoned Dragreder to perform his Dragon Rider Kick alongside Blade's Lightning Sonic against Super-1 and Stronger.

In the History Modifying Machine's altered history, "Shocker Rider Ryuki" summoned Dragreder while attacking Kamen Rider Drive. Though Ryuki was later erased by the Rider Robo, he and Dragreder's place in history would be restored once the Machine was destroyed by Shurikenjin Tridoron.

As a result of the Ryuki Ridewatch, Dragreder served Oma Zi-O in the dystopian future of year 2068. During Zi-O and Tsukuyomi's arrival to the future, Dragreder was summoned to intercept Zi-O when he attempted to attack using Ryuki's power in Ride HeiSaber.

Dragreder was originally an above-average Mirror Monster that went after Shinji, constantly stalking him and trying to find a chance to devour him. When Shinji formed a contract with him, however, Dragreder looked upon him with a strange aura of analysis, suggesting that he was wondering whether Shinji was truly worthy of forming a Contract with him.

Over the course of the war, Dragreder would sometimes be annoyed with Shinji when he stops him from feeding on Mirror Monster energy, and was especially annoyed when Shinji's horror at supposedly taking Gorou's life caused him to stop fighting. This caused Dragreder to try eating Shinji, but was stopped by Yui.

By the end of the war though, it seems some of Shinji's personality has rubbed off on Dragreder, who sometimes comes to his aid without being summoned through Advent and responding to emotions of distress and anger.