The first of the Grongi to appear, Gumun first appeared in south Nagano weaving a web on the 1532 MK Building, overwhelming law enforcement as he attacks them without mercy with his power to spray webbing and create claw extensions on his hands. Crashing into the police station, Gumun slaughters the police officers until Yuusuke puts on the Arcle, being targeted by the Grongi as he becomes Kuuga in "Growing Form" in a fight that ends with Gumun being knocked out of a helicopter several feet in the air. Surviving the fatal fall, Gumun reappeared to settle the score while aiding Gooma. But in the end, the Zu was mortally wounded by Kuuga, screaming his intent to kill Kuuga as he explodes.

Among the first Grongi in Nagano, the photophobic Gooma sucks the blood out on five humans in a single night. In daylight he murders Father Jose and dons his attire to use the Church as a base of operations. He managed to overpower Kuuga until being driven away. When Ichijo uncovered the truth, he battles Gooma as the church is set on fire and Yuusuke fights too. However, though he had the advantage with Gumun's aid, Gooma retreats when dawn occurs. Later donning a black trench coat and fedora to protect himself from direct sunlight, Gooma was temporary removed from the game as a result and becomes Ra-Baruba-De's underling when the Zu lose the right to play. He later refines and uses a discarded piece of Daguva's body to evolve to a state where he can now resist sunlight called the Strengthened Form. But the evolution increased Gooma blood-lust as he actually attacks Baruba to force Daguva's location out of her with the intent to get all Daguva's power. But when Gadoru overwhelms him to cover Baruba's escape, Gooma is forced to retreat as the final stages of his evolution take effect, becoming the armored Ultimate Form. Going on a killing spree in Chiba, killing as many people as he could before Daguva comes for him. But Kuuga arrives to fight him in Titan Form as Ichijo uses a device specially made to disrupt Gooma's via sound waves. But Gooma manages to destroys the device and was about to kill Kuuga when Daguva finally arrives. He runs off to fight Daguva, only to be slaughtered by him with his corpse found by Yuusuke and Ichijo as it is taken for medical analysis, leading to the development of the Nerve-Breaking Bullets.

Mebio, assumes the form of a woman dressed in black,was one of the first Grongi that appeared in Tokyo. She was able to run up to 270 km/h, she fought Kuuga and ended up losing her eye to gunshots by the police, killing Enokida's husband in the process. She was eventually destroyed by Kuuga after recovering from her wound.

The arrogant Baduu assumes the form of a young man with a scarf. When he begins his part in the game in Suginami, Baduu grabs unsuspecting people where the smoke from a factory doesn't point, leaping high enough so his victims can fall to their death. Kuuga arrives before Baduu kills a police officer, with Baduu overpowering Kuuga, though he retreats when the smoke comes their way. Baduu later resumes the game, almost killing Ichijo and attacking the Police before Yuusuke arrives to finish the fight. Though losing at first, Kuuga manages to master Dragon Form's power thanks to Sakurako and kills Baduu.

The leader of the Zu, Zain is able to assume the form of a hulking strongman with a temper. Soon after the Me group's turn begins with the Zu no longer worthy to play, and when their first hideout got compromised by the police's smoke bombs, Zain starts acting on his own by attacking trucks and jabbing the drivers to death with his horn. He overpowered Kuuga in both human and Grongi forms when Biran intervened as Zain stole his turn. While Zain resumes his attack on large motor vehicles, Yuusuke manages to perfect his Mighty Kick to finally kill the Grongi.
A whale Grongi labeled "Unidentified Life Form #7". Destroyed by Kuuga Mighty Form's Mighty Kick.
A kangaroo Grongi abeled "Unidentified Life Form #8". Destroyed by Kuuga Mighty Form's Mighty Kick.
A Sea slug Grongi labeled "Unidentified Life Form #9". Destroyed by Kuuga Mighty Form's Mighty Kick.
A Nepenthes Grongi labeled "Unidentified Life Form #10". Destroyed by Kuuga Mighty Form's Mighty Kick.
An octopus Grongi labeled "Unidentified Life Form #11". Destroyed by Kuuga Mighty Form's Mighty Kick.
Zu-Nezuma-Da and Zu-Nezumo-Da
Rat Grongi labeled "Unidentified Life Form #12A" and "#12B". Nezuma died a mysterious death in an explosion by a police force's gunfire and Nezumo was destroyed by Kuuga Mighty Form's Mighty Kick.
A gecko Grongi labeled "Unidentified Life Form #13". Destroyed by Kuuga Mighty Form's Mighty Kick.
Other Grongi :: Zu Group | Me Group | Go Group
Series:  Kamen Rider Kuuga