Mega Monster Battle: Ultra Galaxy Legends The Movie (2009) on Netflix

Plot summary

Mebius defeats a Bemular on a desert moon and returns to the Land of Light in Nebula M78, where Ultraman, Zoffy and Ultraseven are waiting. At the Space Prison above the planet, Alien Zarab disguises himself as an Imitation Ultraman, subdues the guards and frees the prison's only inmate, Ultraman Belial, who reclaims the Giga Battlenizer. Belial overwhelms the Ultras sent to contain him, then storms the Plasma Spark Tower and takes the Plasma Spark, and the planet begins to freeze. Mebius is told to seek out Rei. Mebius finds him on Dent, an Earth-like world, after Rei's fight with a Zaragas. In his human form, Mirai Hibino, Mebius explains how the Plasma Spark created the Ultramen and how Belial's hunger for its power led to his exile. Rei agrees to help face Belial.