|This article is about a/an episode in Tensou Sentai Goseiger.|
The Earth Purifying Knight of Destiny (地球を浄める宿命の騎士 Hoshi o Kiyomeru Shukumei no Kishi) is the eighteenth episode of Tensou Sentai Goseiger.
The Goseiger try to understand Gosei Knight and his desire to destroy human society for its ills as a propeganda-spewing Yuumajuu takes over the airwaves.
After learning more about the Yuumajuu from the Master Head and that Gosei Knight is an evolved Headder, the Gosei Angels learn that Gosei Knight is attacking an industrial plant. As they confront Gosei Knight in an attempted to stop him from destroying the building, they learn more about how he gained his current form by making a pact with the planet as its protector after losing contact with his Gosei Angel allies in the past. While this occurs, Makuin revives Zeibu of the Mummy as he turns the staff of TV Azuma into his mummified slaves to air his deadly Yuumajuu channel. Nozomu brings it to their attention as the Gosei Angels arrive to the TV studio. But they are halted by the Bibi Soldiers under Buredoran, reintroducing himself as the Yuumajuu Buredoran of the Chupacabra, while Zeibu barricades the building with a barrier. As Buredoran leaves, Groundion arrives to destroy the building. Assuming his humanoid form, Gosei Knight gives the Goseigers five minutes to save the humans inside with Gosei Red reasoning with him. Managing to get in through the basement, the Goseigers fight their way through Bibi Soldiers as time runs out before the Landick siblings are forced out while covering their allies. As the Landick siblings try to keep Gosei Knight at bay after time is up, the others battle Zeibu in a televised fight. Bringing Zeibu outside, the Goseigers stand aside as Gosei Knight defeats Zeibu and breaks his hold over the people. But when the Bibi Bugs revive Zeibu, Gosei Knight sees him no longer a threat to the world as he accepts Gosei Red's offer to watch them fight in Gosei Great, using alternate formations to weaken Zeibu before forming Hyper Gosei Great to destroy him. As Gosei Knight takes his leave, still seeing the Gosei Angels' intent on saving people to have no meaning in saving the Earth, Buredoran thinks up a scheme to make use of him.
- Alata (アラタ Arata): Yudai Chiba (千葉 雄大 Chiba Yūdai)
- Eri (エリ): Rika Satoh (さとう 里香 Satō Rika)
- Agri (アグリ Aguri): Kyousuke Hamao (浜尾 京介 Hamao Kyōsuke)
- Moune (モネ Mone): Mikiho Niwa (にわ みきほ Niwa Mikiho)
- Hyde (ハイド Haido): Kento Ono (小野 健斗 Ono Kento)
- Gosei Knight (ゴセイナイト Gosei Naito, Voice): Katsuyuki Konishi (小西 克幸 Konishi Katsuyuki)
- Nozomu Amachi (天知望 Amachi Nozomu): Sakuya Nakamura (中村 咲哉 Nakamura Sakuya)
- Professor Shuichiro Amachi (天知秀一郎 Amachi Shūichirō): Louis Yamada LIII (山田ルイ53世 Yamada Rui Gojūsan-sei)
- Datas (データス Dētasu, Voice): Kōki Miyata (宮田 幸季 Miyata Kōki)
- Makuin of the Blob (ブロブの膜イン Burobu no Makuin, Voice): Chafurin (茶風林 Chafūrin)
- Kinggon of the Bigfoot (ビッグフットの筋グゴン Biggufutto no Kingugon, Voice): Kosuke Takaguchi (高口 公介 Takaguchi Kōsuke)
- Buredoran of the Chupacabra (チュパカブラの武レドラン Chupakabura no Buredoran, Voice): Nobuo Tobita (飛田 展男 Tobita Nobuo)
- Master Head (マスターヘッド Masutā Heddo, Voice): Ikuya Sawaki (沢木 郁也 Sawaki Ikuya)
- Zeibu of the Mummy (ミイラのゼイ腐 Mīra no Zeibu, Voice): Norio Wakamoto (若本規夫 Wakamoto Norio)
- Io Tosaka (戸坂イオ Tosaka Io): Yua Saito (齊藤夢愛 Saitō Yua)
- TV Announcer: Takahiro Sakamaki (酒巻誉洋 Sakamaki Takahiro)
- Gosei Red - Twistornado, Gosei Dragon, Gosei Great, Hyper Change Headder, Hyper Gosei Great, Victory Charge (Hyper Gosei Great)
- Gosei Pink - Gosei Phoenix, Gosei Great, Hyper Gosei Great, Victory Charge (Hyper Gosei Great)
- Gosei Black - Landick Brothers, Rockrush, Gosei Snake, Gosei Great, Hyper Gosei Great, Victory Charge (Hyper Gosei Great)
- Gosei Yellow - Landick Brothers, Gosei Tiger, Gosei Great, Hyper Gosei Great, Victory Charge (Hyper Gosei Great)
- Gosei Blue - Gosei Shark, Gosei Great, Seaick Brothers, Hyper Gosei Great, Victory Charge (Hyper Gosei Great)
- Gosei Knight - Groundion, Rockrush, Presshower, Comprethunder, Vulcan Headder, Knight Dynamic
- to be added
- This episode aired alone on Super Hero Time due to the preemption of Kamen Rider W, episode 39, The Likelihood of the G/Bad Cinema Paradise due to TV Asahi's sports events.
- Viewership: 5.0%
- Opening: The "destruction of Warstar" scene is replaced with the three main members of the Earth Condemnation Group Yuumajuu: Makuin of the Blob, Kingugon of the Bigfoot and Buredoran of the Chupacabra
- Pre-Break: Gosei Red
- Post-Break: Gosei Red
- This episode aired on the same day of the fourth episode of Super Sentai Versus Series Theater, featuring pt. 2 of Gekisou Sentai Carranger vs. Ohranger
- The preview for this episode in Versus Sentai Theater ended up connecting Gosei Knight to MegaSilver, who would be appearing in the next Vs. Movie
- Brajira of the Messiah Battle Footage was used for "United We Stand" but Zeibu of the Mummy was not used for Power Rangers Megaforce.
Tensou Sentai Goseiger Volume 5 features episodes 17-20: Epic 17: A New Enemy! The Spectral Demon Beasts, Epic 18: The Earth Purifying Knight of Destiny, Epic 19: Gosei Knight Will Not Allow It, and Epic 20: Fall In Love Goseigers. 
- United We Stand - Power Rangers counterpart in Megaforce. See comparison page. (Vrak Battle Footage)
- Robo Knight (episode) - Power Rangers counterpart in Megaforce. See comparison page.
- Ultra Power - Power Rangers counterpart in Megaforce. See comparison page.