Gosei Knight

"The Knight sent to purify this planet! Gosei Knight!"

Gosei Knight (ゴセイナイト, Gosei Naito?) is a mysterious warrior of which the Gosei World has no record of.

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 AkaRanger 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. AkaRanger 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 Furher 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 Furher'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.

Arsenal
Vulcan Headder (バァルカンヘッダー) Gosei Knight's personal Headder, which resembles a gatling gun. It combines with the Leon Laser and the Leon Cellular to add the aforementioned gatling-gun properties to the weapon.
 * Knight Power Releasement Vessel Leon Cellular (ナイトパワー解放器レオンセルラー): The Leon Cellular is Gosei Knight's device that allows him to perform Tensou Techniques via a three-digit code on his cards.
 * Leon Laser (レオンレイザー): The Leon Laser is Gosei Knight's personal weapon. It has both a gun mode and a sword mode called the Leon Laser Sword (レオンレイザーソード), able to perform the Knight Metallic (ナイトメタリック) attack. LeonLaser_Sword.jpg
 * Dynamic Leon Laser (ダイナミックレオンレイザー): Combination of the Leon Laser, the Leon Celluar, and the Vulcan Headder. Gosei Knight performs the Knight Dynamic (ナイトダイナミック) finishing attack. Gosei Knight says "Conviction of Knightick Power!" (断罪のナイティックパワー！) and "Punish!" in performing the finishing attack.

Mecha

 * Groundion Headder (グランディオンヘッダー): Gosei Knight's true form, he accesses this form through the Groudion Change Card.
 * Groundion (グランディオン): A lion/dump truck combination. He can preform the Groundion Laser, shooting an energy beam while launching a torrent of missiles.
 * Knight Brothers (ナイトブラザー): A duo of Gosei Machines composed of the lion/blimp, Skyon and the lion/cruise liner, SealeonImagesCAF9G0CH.jpg.
 * Gosei Ground (ゴセイグランド): Gosei Knight's mecha, formed from Groundion and the Knight Brothers (Skyon and Sealeon).

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.

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.

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.

Trivia

 * Gosei Knight is a Ranger that was originally a mecha, similar to the Spirit Rangers from Jungle Fury. Unlike the Spirit Rangers, Gosei Knight is based on a new mecha, not a already introduced mecha.
 * Gosei Knight is similiar to Seijuu Sentai Gingaman's Bull Black, as he is a non-human Sentai Ranger that can become his own mecha and was originally uncaring of his team.