The Great Ultra War (ウルトラ大戦争 ウルトラ大戦争 Urutora Dai Sensō), also called the Ultimate War (ウルティメイト ウォーズ Urutimeito Uōzu) was a conflict that pitted the army of the Alien Empera known as The Emperor, against the Ultra beings of the Land of Light over 300,000 Earth years ago. Although The Emperor temporarily managed to takeover the planet, the people of the Land of Light fought back and defeated him.
During War Events
Although the events are unclear, it is known that Emperor took control of the Land of Light after leading the most successful attack on the Ultras, something that various Ultramen foes had trouble doing. However, his reign was short-lived as the beings of light fought back, initiating the battle between light and darkness.
At the end of the war, Alien Emperor and Father of Ultra engaged in their infamous duel that decided the fate of the Land of Light. The results came to a draw and both powerful fighters earned mirroring scars on their hips as a reminder of their brutal battle. Emperor, weakened by Father of the Ultra's Ultimate Sword, fled into hiding for generations.
After the war, Ultraman King had Father of the Ultra establish the Space Garrison to protect and watch the Land of Light as well as the rest of the universe in case a crisis like this ever happens again.
One of the Ultra Warriors that fought in the war, Ultraman Belial, became wary of the possibility of another assault on the Land of Light, and tried to take the power of the land's artificial sun, the Plasma Spark. Belial failed to control the Spark power and was driven out of the Land of Light for his deed. However he sought revenge and returned as a Reionyx with his own monster army, and in turn Belial became the very threat he originally intended to avoid.
The War had an impact on various species, how many and the influence is unknown but Alien Temperor wanted to follow Emperor's example to conquer the Land of Light, which ultimately failed.
Years later, Emperor would make his full return to Earth where he would cause most of the events in Ultraman Mebius. However, he was defeated and ultimately destroyed by Ultraman Mebius Phoenix Brave Mode, making Mebius the first and only Ultra to ever accomplish such a feat.