Garban
From planet Garba, the Garbans (are the final alien menace the Gransazers battle with. Appear in Episodes 46-51.

Belzeus
Belzeus is member of the Warp Monarch council and leader of both the Garban and the Earth Invasion Force, the one who set up the war after making his fellow member believe the human race descend from the Bosquito race. In truth he wanted to take over Earth in order to gain a vital place in conquering the universe. To that end, he creates supports to his claim by having using Logia to destroy Crystal Slab to hide the truth and
Luka to resurrect the last Bosquito to give Warp Monarch to attack Earth in full fury. When both failed, Belzeus decides to capture Ran and kill her before her abilities as the Communicator fully manifest, sending his Garba soldiers to exterminate both her and Ruby. Belzeus then arrives on Earth to personally kill Ran, defeating Pisces, Velsou, and Tragos. But when Ran's power as the Communication are finally invoked and contacted to Warp Monarch's will, Belzeus' plans are revealed as Warp Moncarh allows the Gransazers to destroy both Cabryon and the Garban mothership. With his plans ruined, Belzeus is knocked out by Logia as he takes the Garban to be brought before the Warp Monarch council to face judgement. Appears in Episodes 40-51.

Brighton
A Garban Emissary sent to Earth during a three-day ceasefire period, Brighton fakes sympathy for Earth's safety by asking the JSDF to let him investigate the Gransazers, finding Ran as Communicator and claiming her to have Bosquito DNA so that he would give them reason to let him take her, thus leaving Earth with a Communicator to contact Warp Monarch. When ordered by Belzeus to kill Ran before her power is can awaken, Brighton summons Algol to carry out the task. But when Algol fails, Brighton reveals his true colors as Troius sneak attacks the city. Later, while the others destroy Algol, Tarious goes after Brighton as the Garban pretend to beg for his life so he can kill Tarious with his guard down, only to be shot down by Logia. Appears in Episodes 46-48.

Troius
A giant alien monster sent from the Fleet to attack the Earth once the ceasefire ended. Dolcrus and Leviathan battle the beast with aid of the GranVehicles and Yuuhi. But the fight ends with Dorcus heavily damaged, Yuuhi dismantled, and Tappei wounded. After Garuda got damaged as well, Guntras and Cloud Dragon intervene and destroy Troius.

Algol
Serving under Brighton, Algol , is sent to kill Ran, though Ruby stops him when he overpowers Tarious and the Earth Tribe. After Brighton brings Ran to Algol, Tenma saves Ran as he battles Agol. When Ran finds Agol to have him kill her when Ruby interferes again as Tarious and Lion arrive to save the two. Algol later attacks the JSDF as the Gransazers arrive and kill him. Appears in Episodes 46-48.

Gorgion
Sent by Belzeus to exterminate Ruby before she could awaken Ran's power, Gorgion attacks the JSDF before being hindered in his mission by Dail, who manages to defeat before injuring Velsou. But Tarious arrives to hold him off with aid from Gorbion and Realms as Mirthas takes Ryouko and Ruby away. However, Logia turns the tables as he and Tarious double-team Gorgion and the Impactor about to kill him when Tarious' intervened, allowing Gorgion to escape. He is given one last chance to redeem himself by using Cabryon as a distraction to keep the Gransazers off his back while he kills Ruby without interference. After finding Ruby, Gorgion is halted by the Flame Tribe. But after an attempt to use Mirthas as a shield, activates the bomb on his person to complete his mission. Appears in Episodes 49-50.

Kabrion
Arriving in a fireball, Kabrion is used by Gorgion to attack the JSDF to draw the Gransazers out into the open to complete his mission. Kabrion succeeds in damaging Guntras to keep the Gransazers from forming DaiSazer and wrecks the other Chouseishin while appearing to kill Tenma. But once Warp Monarch acknowledges the truth about Earth, the Chouseishin are restored and form DaiSazer to kill it. Episodes 50-51.