Interstellar Alliance (星間連盟 Seikan Renmei) is an intergalactic peacekeeping organization that mainly operated in the World of Planet O-50. Despite their noble reputation, later publications would reveal that the Alliance is corrupt, having engaged in multiple questionable acts behind the scenes.
Ultraman Orb Chronicle
The Interstellar Alliance first appeared during Gai Kurenai's quest for the elements in his Orb Calibur. He actively helped them arresting criminals at the same time. When Jugglus Juggler, Gai's former companion and one of the alliance's wanted criminals, launched a prison riot in Planet 484, an officer was forced to seek Gai's help in fulfilling Juggler's demand, who also helped neutralizing the riot at the cost of his companion, Shorty.
The Blue-Eyed Girl Whose Name is Gray
The Interstellar Alliance was revealed to the one who conspired with Mr. Largo (ラルゴ氏 Rarugo-shi) in claiming Planet Dontak for themselves under the false pretense of modernizing it. Largo had Bakubarba send the three mercenary siblings; Rosso, Blu and Grigio to eradicate Nero so his mercenaries could perform a genocide on the entire Bosco Tribe. While Largo excavated all the rare minerals for himself, he later sold Dontak for the Alliance to build their Supply Transfer Ship. After the three siblings were chosen by the Voice of Light to become Ultraman Rosso, Ultraman Blu and Grigio Bone, the Interstellar Alliance recruited them into their cause in order to have the Ultras to their side. The siblings then discover that Bakubarba had been silently turning her orphanage into a child trafficking hub (with the Alliance's approval as well) and Grigio killing her in a fit of rage. Although the Alliance compensated their actions with putting the orphans under their care, they still lost the siblings anyway during a fight with Leugocyte.
Tregear's Story/Blue Shadow
Although they do not appear in the novel, the Interstellar Alliance is said to manage Planet Tutuola as a garbage disposal planet.
The Interstellar Alliance hired Fuma to get rid of a certain monster who was seen killing people who attempted to get to the Crusader's Peak, having been witnessed by the son of one of the organization's executives. The monster turned out to be Fuma's mentor, Gerg. While they fought, the Interstellar Alliance's hitmen suddenly appeared and attempted to kill them both together. Fuma survived the ordeal after he was brought to the Voice of Light by Gerg and transformed into an Ultraman.
- Prison Planet 484 (監獄惑星484 Kangoku Wakusei Yon Hachi Yon): A planet that serves as a prison center for criminals detained by the Alliance.
- Planet Dontak (惑星ドンタク Wakusei Dontaku): Sold to the Alliance through a deal with Largo, which they used for a massive Supply Transfer Ship.
- Planet Tutuola (惑星チュツオラ Wakusei Chutsuora): A waste disposal planet.