Eldran Series

The is a toy and anime franchise begun by toy company Tomy in Japan, as a subsidiary with the Brave Series. Following the success of the Brave Fighter Exkizer, Tomy also struck a deal with Sunrise to merge with Takara in 2005 and became TakaraTomy, making the Eldran Series being partially regarded as part of the Brave Series. A key difference between both series is that they all revolve around grade schoolers whereas the Brave Series' protagonists ranged from children to teenagers. The series was very popular in East Asian countries.

The first entry, was the first to broadcast in Japan from April 3, 1991 to March 25, 1992. It was the only Eldran Series in 2014 to receive an English dub and dual-audio DVD release by Anime Midstream, with a 4-episode OVA released for Japan from August 5, 1992 to February 24, 1993.

The second entry, aired from April 1, 1992 to February 24, 1993.

The third entry,  aired in Japan from March 3, 1993 to February 23, 1994. as the last TV installment of the franchise.

The final entry, is the fourth installment to be co-created and funded by Sunrise and Dengeki Hobby Magazine.

Plot
Evil entities threaten the planet Earth, and the light guardian entity known as Eldran fends them off and entrusting the planet's safekeeping to chosen grade schoolers with powerful transforming robots.

Zettai Muteki Raijinoh
The evil Jyaku Empire (ジャーク帝国 Jāku Teikoku) comes to Earth with the intent to conquer and despoil it, by flooding the world with Akudamas (アークダーマ, Ākudama), darkness eggs that hatch into evil monsters based on things that annoy or frustrate humans. Eldran thwarts off the Empire and stoops its striking missile with the heroic robot Raijin-Oh, but the missile detonates and throws Raijin-Oh down to Earth, eventually crashing into Japan's Hinobori Elementary school. With the universe still in need, Eledran leaves and entrusts Raijin-Oh and earth's protection to the hands of school's class 5-3, now becoming the Earth Defense Class (地球防衛組, Chikyuu Bouei Gumi).

Genki Bakuhatsu Ganbarugar
The story takes place in Aozora City following one year after Raijin-Oh's victory over the Jyaku Empire. A great demon king of the Demon World (大魔界 Daimakai) was inadvertently unsealed by Kirikagure father and son, Toubei and Kotaro. But Eldran manages to contain him, but one of his servants manages to escape and pursuits his quest to free his master. To fend off the wizard's plot, Eldran entrusts a new heroic robot named Ganbarugar to Kotaro and his two friends, Yosuke and Rikiya, as well as super-powered suits. Although they manage to secure their first victory through luck, the three children along with Toubei were cursed into dogs, but the supersuits safeguarded the children from becoming dogs unless their secret identity is revealed. Now as the Miracle Ninjas Ganbar Team (ミラクル忍者ガンバーチーム Mirakuru Ninja Ganbaa Chiimu), Kotaro, Rikiya and Yosuke defend Aozora City from the dark wizard, Yaminorius III through Toubei's ninja guidance and secrecy.

Nekketsu Saikyo Gosaruer
The Mechanization Empire (機械化帝国, Kikaika Teikoku) invades the solar system, and has mechanized Neptune, Uranus, Saturn, Jupiter, and Mars, and set their sights on Earth in the Mesozoic Era, the age of the dinosaurs. However, Eldran stands in their way with the dinosaur-themed robot Gosaurer to fight against this menace. The three dinosaur robots that combine into Gosaurer chose Harukaze Elementary students, Kenichi Minezaki, Hiromi Tachibana and Shinobu Asaoka as their pilots, and later the entire Class 6-2 where the three and their classmates become the Saurers team. The class fends off the Empire in their attempts to prevent Earth from becoming a mechanical deathstar, as a well as struggling through the burden of growing up in their last year of grade school.

Kanzen Souri Daiteioh
A year after the Mechanization Empire's defeat, Eldran combats against new invaders that approach Earth, an organization of space ogres called the Onigashima. To stop this new threat, Eldran sends Raijin-Oh, Ganbarugar and Gosaruer to fend them off, but were easily overpowered and entrapping them into a giant golden sword. The golden sword lands upon Gokuraku Elementary, turning the whole school into a battleship base of operations for a new light of victory called Daiteioh. The chosen children are "Dangetsu"; Gokuraku's Class 5-3 where the students idolize the Eldran robots and their respective defense teams; the Earth Defense Force, the Ganba Team and the Saurers. Together, the class fight against the Onigashima as they inherit their predecessors' will as Eldrans' next chosen.