Gosei Knight

"The Earth purifying knight of destiny, Gosei Knight!"

Gosei Knight (ゴセイナイト, Gosei Naito) is a mysterious warrior of which Gosei World has no record. He comes to identify with the Goseigers.

Biography
Ten-thousand years ago, he was originally the Groundion Headder (グランディオンヘッダー, Gurandion Heddā) and battled the Yuumajuu until he got separated from his Gosei Angel allies. Ending up in a glacier, Groundion made a pact with the planet itself as it gives him the means to assume his human-like form to fight the revived Yuumajuu and cleanse the Earth of any threat to it. His motivations however have put him at odds with the current Goseigers, as he doesn't care for the people who inhabit the Earth. However, the more time he spends on Earth fighting alongside the Goseigers, the more he begins to realize that their missions are one in the same.

Unlike the Goseigers, Gosei Knight uses the mysterious Knightick Power (ナイティックパワー, Naitikku Pawā), enabling him to use the abilities of the Skick, Landick, and Seaick Tribes. When fighting, he refers to himself as "The Earth purifying knight of destiny! Gosei Knight" (地球を浄める宿命の騎士！ゴセイナイト, Hoshi o kiyomeru shukumei no kishi! Gosei Naito). Before performing his finishing attack, he calls upon the Conviction of Knightick Power (断罪のナイティックパワー, Danzai no Naitikku Pawā). Gosei Knight debuted in Epic 17.

Just a few weeks after Brajira's defeat, Gosei Knight unexpectedly is forced to face the sudden arrival of the Space Empire Zangyack on Earth, who rendered him and the rest of the Goseigers helpless. After the arrival of Akarenger and Big One, he fought alongside not only his own team, but every single Sentai ranger in existance, against the Zangyack when it attacked the Earth in the Great Legend War. After fighting against hundreds of Gormin and their Zgormin commanders. Akarenger noticed the fleet moving towards them, he gathered all the rangers together and gave them the order to sacrifice their powers to wipe out the first invasion's armada. After losing their powers, the Goseigers agreed that it was nice to lose their powers if it meant saving the world from the space invasion.

Some time later, Gosei Knight (in his Headder form) accompanied the Goseigers in the reclamation of their powers from their successor team, the Kaizoku Sentai Gokaiger. Due to all the powers being transformed into Ranger Keys, he needed his Gosei Knight key in order to regain a humanoid form and fight alongside the other Goseigers. Though the other Goseigers fought the Gokaigers to regain his key, the mess ends up making all of the other Ranger Keys become captured by Black Cross Führer to be used as his slaves. Ironically, his key ends up falling out of the chest before the Führer got away, where it was discovered by he and Navi and used to reawaken his powers as intended. Once the Goseigers and Gokaigers returned from the Führer's other dimensions, Gosei Knight fought the Ranger Key Clones of all the Sixth Rangers and assisted in taking down the enemy before returning his key to the pirate heroes.

Video Game appearances
Gosei Knight appears with the Goseigers in Super Sentai Battle: Ranger Cross.

Ranger Key
The Gosei Knight Ranger Key (ゴセイナイトキー) is Gosei Knight's personal Ranger Key and what became of his powers after he along with the rest of the 34 Super Sentai sacrificed their powers to end the Great Legend War.

This key, along with the other fourteen sixth ranger keys and the ten extra hero keys, were initally acquired by Basco ta Jolokia and later used by the Gokaigers. Like all of his Ranger Keys, Basco used his trumpet, the Rapparatta, to turn the Gosei Knight key into a puppet to do his bidding. The copy Gosei Knight was one of the remaining ten sixth rangers after the Gokaigers defeated the first five, with Basco using these ten to ambush the Gokaigers and take all of them hostage bar Marvelous. When Marvelous rescued them, they defeated all 10 puppets and claimed the Ranger Keys.

For a brief period, the Gosei Knight key was returned to the Groundion Headder to be used by it during the battle with the Black Cross Führer. Initially the acquisition of the key by the Goseiger leads to them and the Gokaiger becoming separated but it allows for Gosei Knight to assist in the major battle against the enemy.

While in the possession of the Gokaigers, the Gosei Knight Ranger Key was mainly used by Gai Ikari (Gokai Silver), who used it to fight as Gosei Knight. It was also used by Joe Gibken on one occasion.
 * Joe became Gosei Knight as part of an all-silver Gokai Change in the Gokaigers' fight with Action Commander Osogain.
 * When the Gokaigers became the Goseigers while fighting Action Commander Stargul.
 * To use the Defenstorm Gosei Card to protect Kenta Date (MegaRed†) from Basco's attempt to take the greater power of the Megarangers.
 * As part of an all-lion Gokai Change which challenged Ninjaman to think of what was the connection of that change.
 * As part of a bombardment of changes in the final battle with Emperor Ackdos Gill.

After Zangyack were finally defeated, the Gokaigers gave the Ranger Keys back to their rightful owners. It is presumed that Gosei Knight received his key and became a knight once more.

Portrayal
Gosei Knight is voiced by Katsuyuki Konishi (小西 克幸). His suit actor is Jiro Okamoto (岡元 次郎).