|This article is about a/an location in Uchu Sentai Kyuranger.|
|This article is about a/an location in Power Rangers HyperForce.|
Kaien (惑星カイエン Wakusei Kaien, Planet Kaien) is a planet in the Shishi System where Lucky was born as a prince, a descendant of the child born over 333 years ago from the union between a woman from the Shishi System and Orion, strongest warrior of the system of the same name. However, when he was only a young boy, Lucky, along with his small companion Caesar and his father’s retainer Jiiya emerged as the three sole survivors as Kaien was ravaged by Kukuruga and his parents were lost, leading to him being adopted and raised on the planet Luth in the adjacent Kojishi System.
It is revealed that the planet’s king Aslan, Lucky’s father was murdered by Kukuruga around the certain incident where Lucky, Caesar and Jiiya survived, and being replaced by an impostor created by the Jark Matter Karo Jumotsu. However, the fate of the queen, Lucky’s mother remained unknown. After the Kyurangers restores Planet Kaien, Lucky finally becoming the new heir of this planet’s throne, receiving his crown from the Kanmuri Kyutama.
Unfortunately, unaware to many inhabitants of Plante Kaien, the real Aslan is revealed to be kidnapped and brainwashed into one of Jark Matter’s servants, until Kyuranger found him alive and save him from Don Armage’s mind control. Yet, the original king prefer to sacrifice his life to save the universe and entrusted his throne for his son.
- Marv Shih and Joe Shih are also citizens of this planet, as revealed in Power Rangers HyperForce. However their location during Don Armage's invasion is left unknown.
- Uchu Sentai Kyuranger
- Space.12: 11 Ultimate All-Stars (flashback)
- Space.36: The Legend That Sleeps in Lucky's Homeworld (flashback)
- Space.37: Lucky, Seen Again With His Father
- Space.41: Rushing! Planet Southern Cross (flashback; archive footage only)
- Space.42: My Father? The Universe? Lucky's Resolution (flashback; archive footage only)
- Space.43: Lucky’s Promise on the Holy Night (flashback; archive footage only)
- Space.44: Don Armage's Identity (mentioned only)