The hero of the series, Ultraman Gaia is the third of the 90s wave of Ultraman heroes, but goes in a different direction from all others. Whereas most Ultra heroes are aliens, Gaia is the embodiment of the Earth itself, willed into existence to protect the planet from the Radical Destruction Bringer. He also has no time limit nor does he require sunlight, instead drawing his power from the Earth's energies. Ultraman Gaia has also gone on to make appearances in other series.
- Anthropomorphic Personification: Unlike every single Ultraman before him, Gaia is a literal embodiment of the Earth's will (especially the element of earth itself) to fight against the Radical Destruction Bringer and protect all of its inhabitants.
- Bash Brothers: With Agul after they settle their differences.
- Blade Below the Shoulder: Courtesy of Agul's light, he can fashion a Agul Blade.
- Critical Annoyance: Like all Ultramen, he has a Color Timer. However, he has no time limit and his Colour Timer only begins flashing if he has taken a lot of damage.
- Finishing Move: Gaia's signature ability is the Photon Edge, which is different from all other examples in the franchise in that he fires it from his forehead. He does also have the more standard "+"-shaped Quantum Stream.
- An Ice Person: Downplayed. Although Gaia primarily uses heat-based attacks (due to his connection with the Earth), he can also perform Gaia Blizzard to freeze his target.
- Kamehame Hadoken: His Liquidator, courtesy of Agul's powers.
- Lightning Bruiser: Gaia Supreme, which combines both the lights of Gaia and Agul.
- Meaningful Name: After the Gaia Hypothesis, or the theory that Earth itself is a super-organism — befitting of an Ultraman created from the Earth itself.
- Mighty Glacier: Gaia V1's fighting abilities involves more on power and strength than speed itself, that is until he gained Agul's light.
- Mid-Season Upgrade: Gains one as Gaia V2 in courtesy of Agul.
- New Powers as the Plot Demands: After receiving Agul's light, not only Gaia upgraded into V2 and transforming into Supreme, he also obtained a few sets of Agul's powers.
- Playing with Fire: Downplayed, in that Gaia utilizes heat as part of his connection with the Earth.
- Red Oni, Blue Oni: The red to Agul's blue.
- Top-Heavy Guy: Gaia's pectoral muscles noticeably grow, especially in V2 and Supreme.
The first Anti-Hero and blue-bodied Ultraman in the franchise, Ultraman Agul was also born from the will of Earth itself (representing the element of the sea). Like his human host, Hiroya Fujimiya, he believes that humans are as much a threat to Earth as the alien minions of the Radical Destruction Bringer are, so unlike Gaia, he pays no heed to human loss of life in his battles and plans on eventually dealing with mankind as well. Ultraman Agul has also made a few reappearances, albeit not as often as Gaia.
- Anthropomorphic Personification: Like Gaia, Agul is born of the Earth's will to defend itself from the alien invaders, but unlike Gaia, he only cares about protecting Earth and not its inhabitants.
- Anti-Hero: The first example in the Ultra Series.
- Bash Brothers: With Gaia after they settle their differences.
- Blade Below the Shoulder: Is the very first Ultraman to do this in the history!
- Came Back Strong: Returns as Agul V2, with his previous attacks turned into stronger versions of themselves.
- Fragile Speedster: Is the fast, stealth and sleeker than the two Ultras.
- Kamehame Hadoken: His Liquidator functions in this fashion.
- Laser Blade: Agul Blade, and by extension Agul Saber for V2.
- Making a Splash: Agul draws his strength from Earth's waters.
- Red Oni, Blue Oni: Obviously he's the blue to Gaia's red.
- The Rival: To Ultraman Gaia, much like their hosts.
- The Worf Effect: Surprisingly to his new form, Agul V2, whose supposed to be stronger than Agul V1 but always get his butt kicked by various monsters if he were to fight first before Gaia. This is averted when both Ultras cooperate.
XIG (eXpanded Interceptive Guardians) Operation Crew
- Played by: Takeshi Yoshioka
- Badass Bookworm: He's both a genius and an Ultraman. By the time Gaia obtains Agul's light, Gamu trains himself more often so his body can catch up with Gaia's increasing strength.
- Butt-Monkey: Expect this when he works with Team Hercules.
- Contrasting Sequel Main Character: To Shin Asuka of Ultraman Dyna. Asuka was hot-blooded and one of the ace pilots of Super GUTS, whereas Gamu is the analyst, and is not usually sent to the front lines to fight.
- Dark and Troubled Past: Was ridiculed by his classmates back in his elementary school. But those days were behind and here, he's an adorable genius who has a great social skills.
- Gadgeteer Genius: As a member of Alchemy Stars, he helped developing all the technology that XIG uses, so he knows how to use it better than any of the assault teams. Not to mention, he built the Repulsor Lift flight system and Esplender to store Gaia's light.
- The Hero: He is the guy who turns into Ultraman Gaia, after all.
- In-Series Nickname: Chewing Gum by Team Hercules.
- Intelligence = Isolation: Downplayed in that the isolation part was only in his childhood due to his entire classmates being Green-Eyed Monster for his prodigy. By the time he enrolled into the university, he has three friends that stick to him and his social skills is comparable to normal humans.
- Mission Control: Unlike most Ultra Series protagonists, Gamu usually remains inside the base as a strategist, only being sent out when the XIG attack teams need the extra support.
- No Social Skills: Averted despite his Dark and Troubled Past.
- The Strategist: Of XIG, since he's the brainiest member of the crew.
- Sweet Tooth: In a pastry shop, he binges over a few sundae after investigating Gan-Q overnight in the next morning. Georgie is understandably creeped out.
Captain Seiichiro Tsutsumi
- Played by: Takashi Ukaji
- The Captain: Of XIG as a whole.
Commander Akio Ishimuro
- Played by: Hiroyuki Watanabe
- Reasonable Authority Figure: Towards Gamu, he accepted the boy's request for recruition and hired him again sometime later after he was fired for his association to Fujimiya.
- Secret Secret-Keeper: He is the only XIG member who knows that Gamu is Ultraman Gaia, which is why he lets Gamu out on the field when the Monster of the Week is causing too much trouble.
- What Measure Is a Non-Human?: In the three final episodes, Fujimiya proposed himself and Gamu to lead the attack against Radical Destruction Bringer now with their identities exposed. Ishimuro refuses and he stated that they are valuable friends instead of weapons.
- Played by: Maria Theresa Gow
- Bridge Bunnies
- Genki Girl: Is usually brighter than Atsuko.
- Red Oni, Blue Oni: The red to Atsuko
- Surprisingly Good English: Courtesy of her actress' origin.
- Played by: Ai Hashimoto
- Bridge Bunnies
- Clingy Jealous Girl: Hates it whenever Gamu approaches other women. Not that she made a progress in their relationship.
- Date Peepers: For once with Gamu when stalking Kajio's visit to her sister.
- Friendless Background: Due to her Ill Girl status forbids her to participate in the school sport.
- Ill Girl: Has this past and thus preventing her to have a social life in school.
- Gamer Chick: Is implied to be this before her days in XIG, and this skill is useful when fighting against Crisis Ghost virus.
- Imaginary Friend: Her only companion as a child was a doll named Lilia that she lost sometime ago. This came to hunt her when Psycho Mezard II tries to mess with her mind.
- Not So Different: To The Hero Gamu Takayama, as both had Friendless Background as children.
- Pet the Dog: While usually aggressive towards Gamu (usually because of her Tsundere trait), on one occasion she defended him when Team Hercules nicknames him Chewing Gum, believing it as offensive despite Gamu assuming it as a friendly meaning.
- Running Gag: Starting from episode 42, Gamu being close to Catherine has her snapping a pen.Gamu: Cath...
Atsuko hold her pen on right hand and raising it, and a moment later...
Catherine: Sure, I'll go with Gamu.
- Senpai Kohai: Initially served one to Kajio, who she has a crush for before stepping down for him to go with her sister.
- Tsundere: Type A towards Gamu. Despite her penchant for mocking him, she does actually care a lot for Gamu. Twice, she has even felt an intense jealousy when Gamu started hanging out with another girl.
Staff Officer Tatsumi Chiba
- Played by: Sei Hiraizumi
- Played by: Ayaka Tanaka
- Bridge Bunnies: The least frequently appearing of them only being seen whenever Georgie or Atsuko aren't available for whatever reason.
- The Stoic: Is basically this during her job.
- Voiced by: Kazuhiko Watanabe (series), Hiroshi Kamiya (Once Again Gaia)
- Companion Cube: To Gamu.
- Played by: Masami Nakagami (Katsumi Kajio), Katsuhiko Hasegawa (Yasushi Kitada), Yusuke Sawaki (Satoshi Ogawara)
- Second Love: Kajio is one to Atsuko's sister.
- Senpai Kohai: The Kohai to Team Falcon as a whole. Kajio is also one towards Gamu and Atsuko.
- Undying Loyalty: Ogawara respects his leader Kajio, even if he is younger than the former. He also forms one to Gaia when he refused to shot down the impostor Ultraman.
- Played by: Kurunosuke Kagawa (Tatsuhiko Yoneda), Shogo Shiotani (Koichi Hayashi), Shin Ishikawa (Toru Tsukamori)
- Older and Wiser: Unlike Team Lightning, they are more willing to listen to Gamu's advise.
- Senpai Kohai: The Senpai to Team Lightning as a whole.
- Played by: Tomoko Kawashima (Miho Inagi), Izumi Matsuda (Julie Mishima), Kei Ishibashi (Kei Tadano)
- Action Girl: ALL OF THEM!
- Tomboy with a Girly Streak: Kei Tadano. Although she hits the gym and hears rock music as much as her team members, her feminine side surfaces whenever she is with Team Falcon leader Yoneda.
- Played by: Masaru Matsuda (Satoru Yoshida), Koji Nakamura (Takanobu Kuwabara), Kei Kagaya (Mitsugu Shima)
- Gentle Giant: As a whole. Gamu is usually burdened by their hyperactivity but is otherwise on good terms with them.
- Played by: Shunsuke Gondo (Atsushi Koyama), Tomu Saeba (Renji Matsuo), Samuel Pop Aning (Michael Simmons)
- Played by: Tsukiya Kageura (Katsutoshi Yokotani), Hiroaki Irisawa (Gentaro Imai), Naoyuki Yokoyama (Kingo Iwao)
- Butt-Monkey: They almost never get sent on any missions to the point of Running Gag. When they are assigned to help Gamu deal with Candea, they get super excited about it.
- Played by: Hiroshi Ishii
- Men in Black: Dressed as one.
Hirokoyuki HiiragiThe head of GUARD's Pacific unit (which operates on both sides of the ocean), and a vehemently anti-monster warrior.
- Well-Intentioned Extremist: Wants to exterminate monsters (both good and bad) for the sake of humanity.
Alchemy StarsA scientific organization of child prodigies founded in the 1980s. They created the Crisis computer in 1997, discovering the prophecy of the Radical Destruction Bringer's apocalypse and starting the events of the series. Gamu was a former member of the group.
- Played by: Hassei Takano
- Anti-Hero: Although Fujimiya fights the Radical Destruction Bringer's forces like Gamu, he does not care for humanity and plans on eventually dealing with them as well. This frequently leads to conflict between them.
- Badass Bookworm: Like Gamu, he is also a genius and has been training his body to become a capable fighter (granted that he bonded to Agul 3 years earlier than Gamu with Gaia). His old home shows him having a set of gym equipment.
- Bar Brawl: Gets into a fight with several patrons, fueling his racism on humanity.
- Brought Down to Normal: In-between episodes 36 to 40, he's on his own resource after relinquished Agul's light.
- Fiction 500: Is rich enough to own a private jet!
- Gadgeteer Genius: As a member of Alchemy Stars. He created the Crisis supercomputer, as well as his Agulater and technology that would allow humans to redirect monsters away from urban centers.
- Heroic BSoD: Boy, he didn't took the revelation of being tricked by an infected Crisis very well. The next thing he do is to unleash a huge scream and gives Gamu Agul's light.
- He Who Fights Monsters: Tries to eliminate humanity, whereas he is also one of them.
- Humans Are Bastards: Subverted that he was fooled into thinking this by CRISIS.
- I Let Gwen Stacy Die: Greatly traumatized by the death of Kyoko Inamori when her attempt to control Gomenos failed.
- Jump Scare: The still Heroic BSoD Fujimiya gives one to the viewers in episode 41, right in the beginning of the episode.
- Pet the Dog: In episode 20, he released Geschenk towards the city to destroy humanity. In that same episode, he rescued a young girl from several falling rubble.
- Skunk Stripe: Sports one from episode 41 up until the series' finale.
- Stop, or I Shoot Myself!: Has this moment in episode 36 when GUARD, Reiko and Gamu tracked Fujimiya, who threatens a Taking You with Me by revealing a bomb strapped to his body should GUARD try to arrest him.
- Take Up My Sword: A variation. Fujimiya still lives but is visibly hurt from the revelation of being duped by the Radical Destruction Bringer and relinquished Agul's light to Gaia.
- Taking You with Me: Having relinquished Agul's light, Fujimiya tries to make a kamikaze trip to the wormhole to destroy the Radical Destruction Bringer. He fails because the wormhole has an invisible barrier.
- Unwitting Pawn: Becomes one to Radical Destruction Bringer at the first half of the series.
- Well-Intentioned Extremist: Believes himself to be one, as his claims were not entirely wrong. Subverted later on when such believes were created by deceits and lies.
- Played by: Makiko Kuno
- Died in Your Arms Tonight: Dies this way in Fujimiya's hands.
- Small Role, Big Impact: Keepsakes of her research data was kept by Gamu and given to Fujimiya, which proves handy in the re-activation of Crisis in the final episode.
- Undying Loyalty: Is faithful to Fujimiya's belief and path set by the Crisis, with said believe was later on revealed as a lie set by the Radical Destruction Bringer.
- Played by: Debbie Regier
- Badass Bookworm: A non-Ultraman example: she is the leading member of a project in Canada, yet is skillful with the use of conventional weapons to lure Syazac towards a cliff.
- Badass Normal: She even has the guts to take on Syazac by herself!
- Distaff Counterpart: To Fujimiya, as they're both members of Alchemy Stars.
- Fiction 500: Implied. Or else how did she get the money to obtain ranged weapons?
- Foil: Again, to Fujimiya. Unlike the latter, she's one of the good guys through and through. Whereas Fujimiya antagonizes humanity at first until coming to the realization that he's been an Unwitting Pawn to the Radical Destruction Bringer.
- Missing Mom: Overlapping with Disappeared Dad, as both of her parents died in an accident when she was a child.
Daniel McFeeThe American chairman of Alchemy Stars.
Kanto Community Broadcasting (KCB)
- Played by: Yukari Ishida
- Intrepid Reporter: She tends to get heavily involved in the Monster of the Week adventures because of this.
- Morality Pet: Is the first human aside from Kyoko who Fujimiya gets along well with.
- Played by: Hiroshi Tsuburaya
- Put on a Bus: The Once Again Gaia OV has his gone on a trip to Bosnia. This is because at the time of production, his actor passed away months before.
- Played by: Eisuke Tonoda
Ritsuko SasakiAtsuko's older sister.
- Second Love: Finds one in Kajio.
- Widow Woman: Lost her husband from a battle with COV. He was a GUARD pilot at that time and said monster took down his fighter.
Shigemi and Yuiichi TakayamaGamu's mom and dad respectively.
Sato, Makoto, and NakajiGamu's college buddies.
- Power Trio: All of them
- Satellite Character: They rarely ever had any chaarcterization beyond being Gamu's friends. The closest we ever got to see them was if one of them had involvements with a Monster of the Week.
Megumi KurodaA friend of Tabata and an expert in Feng Shui, first showing up to assist KCB in investigating the appearance of Mizunoenoryu.
Yabuki ShiroigaiThe head of a cult obsessed with the coming of the Radical Destruction Bringer.
The Radical Destruction Bringer
- First Appearance: Seize the Light!
The unseen Big Bad of the series, prophesied to destroy Earth and the human race in the future. It is a mysterious cosmic entity from the M91 Galaxy that believes that Earth is a threat to the universe and sends various monsters to destroy the human race. However, Ultraman Gaia and Agul are not going to have any of that.
- Big Bad: It's the being that sends monsters and aliens to Earth to destroy the human race and has been behind nearly every major event in the series in some fashion.
- The Dreaded: So much that every living being on Earth opposes the Radical Destruction Bringer - even the kaiju.
- The Ghost: Despite being the Big Bad it never actually appears onscreen, but its presence is felt all thought out.
- A God Am I: Believes it has the right to judge whether the human race and all other creatures on Earth deserve to live or die.
- Hypocrite: Claims itself to be a benevolent protector of the universe, but is a hateful and malevolent tyrant that enslaves other creatures and destroys planets.
- Know When to Fold 'Em: It's never destroyed in the end; after the destruction of Zogu, it simply calls quits to its plans and leaves Earth alone.
- Manipulative Bastard: Uses psychological warfare, manipulating humans like Fujimiya and Klaus Eckhart to turn their backs on humanity, lose their spirit to continue resisting, or even make them believe that they should kill themselves off for humanity's benefit.
- Names to Run Away from Really Fast: Radical. Destruction. Bringer.
- Villainous Breakdown: After the humans try to attack it in episode 45, it decides to not play around anymore and sent his most powerful minions.
- First Appearance: Seize the Light!
- Art Evolution: The second C.O.V. is purely white in colour, unlike the first C.O.V. and Super C.O.V. It's explained in supplementary sources that the monster was a female of the species, hence the accompanying babies.
- Blade Below the Shoulder: Possesses Type 3, the blades-for-hands variety.
- Elite Mook: Super C.O.V., which is not only bigger and stronger, but possesses a more powerful version of the normal one's forehead beam.
- Fun with Acronyms: C.O.V. stands for Cosmic (or Cybernetic in some sources) Organism Vanguard, but everyone calls "Kovvu".
- Mini Mook: The Baby C.O.Vs. from Episode 10 "Rock Fight".
- Mooks: They're the Radical Destruction Bringer's basic soldiers.
- Non-Malicious Monster: The Radical Destruction Bringer actually captures C.O.Vs. from their home planet and drops them off on Earth to let them rampage like panicked animals. Otherwise, they're perfectly peaceful.
- Slave Mooks: Revealed to be such in Episode 44. The Radical Destruction Bringer harvests the creatures from their home planet in the M91 Galaxy and send them to Earth to have them destroy stuff in their confusion.
- Starter Villain: For Ultraman Gaia.
- Stock Sound Effects: Its roar is a modified version of the Jurassic Park raptors' hissing.
- Villain Team-Up: With Super Pazuzu in Episode 44 "Attack of the Space Monsters".
- First Appearance: A Hero Apears
- Achilles' Heel: Its Chest Blaster is very vulnerable to damage.
- Back for the Finale: It is among the Earth monsters that joins XIG and the Ultras in the battle to save Earth from the Radical Destruction Bringer.
- Butt-Monkey: All three Geels die, putting them on the same level as Tigris for most deaths by an Earth monster during the series.
- Chest Blaster: Geel has a red orb-like organ on its belly that shoots magma bombs. Of course, being a quadrupeda monster, it needs to stand on its hind legs to use it.
- Magma Man: Its Boss Subtitles is Bizarre Magma Underground Beast, which is evidenced by its Chest Blaster.
- Red Eyes, Take Warning: Has tiny red eyes.
- Tunnel King: Like many of the Earth monsters, it is a proficient burrower.
- First Appearance: His Name is Gaia
- Cyclops: In its humanoid form it has a single yellow eye.
- Expy: Apatee's humanoid form is an homage to the YMS-15 Gyan from Mobile Suit Gundam, both being metallic, one-eyed humanoids covered in armour.
- Extra-ore-dinary: Being the first of the three Metal Organisms naturally lends to this. It also makes lots of metallic noises as it moves.
- Shapeshifter: Its true form is a mass of liquid metal. It takes on a humanoid form in order to battle Ultraman Gaia, but it even turns itself into a giant javelin to try impale Gaia.
- Shapeshifter Weapon: Morphs its hand into a spear for the fight.
- Silicon-Based Life: It's an organism composed entirely of liquid metal.
- Spikes of Doom: Can create several electrified spikes using its own mass to cage opponents.
- Wake-Up Call Boss: Apatee was no pushover compared to C.O.V. and Geel, being the first monster to give Ultraman Gaia a hard time and forcing Ultraman Agul to step in and finish off the creature for Gaia.
- First Appearance: Gamu of the Sky
- Backpack Cannon: Able to fire lasers from its back.
- Big Applesauce: The monster attacks New York City and destroys the Statue of Liberty.
- Combat Tentacles: Its main weapon in melee combat.
- Eldritch Abomination: Is an extradimensional being that looks just plain bizarre.
- Fighting a Shadow: The big issue with it at first: the creature itself exists in another dimension and the entity attacking the city is simply a projection of it rather than its real self. The only way to actually kill it is to drag it into the physical world where it's vulnerable.
- Flying Seafood Special: Its projection form is a giant ghostly jellyfish that is unable to be hit by XIG, but is able to interact them with teleportation, laser blasts, and even turning buildings into sand by phasing through them.
- Our Monsters Are Weird: Like many Ultraman Gaia kaiju, but being a giant walking jellyfish from another dimension earns you a special spot.
- Shock and Awe/Electric Jellyfish: Its tentacles deliver electrical shocks.
- Stock Sound Effects: Had Sharptooth roars in its debut.
- First Appearance: Another Giant
- Diabolus ex Nihilo: Whereas almost all of the monsters in the show are most certainly natural inhabitants of Earth or alien minions of the Radical Destruction Bringer, Bokurag's origins and allegiances are left unclear.
- Energy Absorption: Its pincers can drain Color Timer energy with their grasp.
- Healing Factor: Able to regenerate body parts due to its composition.
- Making a Splash: Bokurag is made out of water, which makes it effectively invisible when swimming.
- Meaningful Name: Named after the Cthulhu Mythos deity Bokrug the Great Water Lizard.
- Sea Monster: Resembles a mixture of a giant lizard, a fish, and a crab.
- First Appearance: The Ridiculing Eye
Because of its bizarre appearance, Gan Q has quickly become one of the most iconic Ultra Series monsters and has made a number of reappearances, starting with Ultra Galaxy Mega Monster Battle, which added it to the Showa continuity.
- Attack Reflector: Gan Q is able to absorb projectiles into its primary eye and fire them back out.
- Ax-Crazy: The psychotic laughter and love of carnage say it all.
- Back from the Dead: In Episode 31, "The Accursed Eye", albeit as a zombie.
- Body Horror: Its second form from Episode 31 is distorted, deformed and appears to be decomposing...
- Breakout Villain: The most famous Ultraman Gaia monster and one of the few to appear in other entries since its debut.
- Eldritch Abomination: Hailing from another dimension and incomprehensible to Gamu's logical mind.
- Eye Beams: Lots of them as you may guess.
- Eyes Do Not Belong There: Its limbs are completely covered in eyes.
- Faceless Eye: Initially manifests itself as one, cackling at Gamu and Team Lightning as they shoot it.
- Giggling Villain: Because it finds everything in our world hilarious, especially when stuff gets blown up!
- Oculothorax: A giant eye with legs.
- Our Monsters Are Weird: Which is probably the reason why Gan Q is considered in Japan to be among the Ultra Series' most iconic monsters, despite showing up a lot later than most well-known Ultra kaiju.
- Our Zombies Are Different: The Voodoo Zombie type in its second appearance in "The Accursed Eye".
- Punny Name: On the Japanese word for eye, "gankyu".
- Teleport Spam: Likes to use this to confuse enemies.
- Tractor Beam: Fire ones from its primary eye that traps whatever it catches inside its body to be tormented by thousands of laughing eyes.
- First Appearance: The Cleansing of the Earth
- Bilingual Bonus: "Tenkai" is Japanese for "heaven", referring to its association with the sky. The kanji is even written on its body.
- Blow You Away: Controls the winds to help it reform the atmosphere.
- Our Monsters Are Weird: Giant flying bells don't usually constitute as kaiju, now do they?
- Spin Attack: Tenkai's constant spinning is what allows it to change the weather, including create a hurricane to shield itself. It also meant that Ultraman Gaia could barely grapple it during the fight.
- Weather Manipulation: Because its purpose is to change the atmosphere, Tenkai can create hurricanes and tornadoes
Anemos and Crabgan
- First Appearance: Ghosts of the Past
- Breath Weapon: Anemos can breathe mind-controlling gas, while Crabgan breathes an extinguishing mist.
- Fusion Dance: The two monsters can merge to transform into a single entity with the powers and strengths of both.
- Giant Enemy Crab: Crabgan, obviously.
- Our Ghosts Are Different: In this case, they're the phantoms of two long extinct creatures seeking to become the Ultimate Lifeform.
- Prehistoric Monster: They both originate from the Cambrian period.
- The Symbiote: Of the mutualism variety, as the two monsters intend on becoming the most powerful creatures in Earth's history through uniting together.
- Ultimate Lifeform: The reason why the two creatures originally formed a symbiotic relationship was to become this and thus never go extinct.
- First Appearance: Seagull Takes Off
- Combat Tentacles: Sprouts a number of these from its body.
- Our Monsters Are Weird: Ultraman Gaia is full of bizarre kaiju, but this thing has to easily rank among the strangest.
- Playing with Fire: Produces a heat so extreme that it could cause the Earth to go down in lava and flames if it somehow got to the Earth's core.
- Rock Monster: It's a bit abstract in shape, but it takes on the form of a large stone when it lands on Earth.
- Spin Attack: Can spin itself rapidly to drill into the earth.
- First Appearance: The Dragon's Capital
- Attack of the Monster Appendage: Type 2. It starts off as multiple dragon heads popping up all over the city, these heads which are later revealed to be part of its entire body.
- Back for the Finale: Helps Ultraman Gaia and XIG battle Zogu and the Dobishi, along with a multitude of other Earth monsters.
- Breath Weapon: Breathes lightning from all nine of its heads.
- Making a Splash: As the god of water, it can control rain and rivers to its liking.
- Multiple-Tailed Beast: Has 8 tails that end in dragon heads.
- Non-Malicious Monster: Mizunoenoryu isn't evil. The only reason why Ultraman Gaia fights it was because the creature was simply angry about the disruption of its home in the waters underneath Tokyo.
- Our Dragons Are Different: Heavily inspired by Eastern dragons, right down to the association with water.
- Power Crystal: The emerald on the main head's forehead creates explosive flashes of energy.
- First Appearance: Monster Encircling Net
- Energy Absorption: As a semi-gaseous entity, Wolf Gas can consume natural gases to grow in size.
- Non-Malicious Monster: Unlike most of the other alien kaiju in the series, Wolf Gas is merely a lost and confused creature, not a minion of the Radical Destruction Bringer. In fact, Ultraman Gaia has to protect the monster from the vehemently anti-alien Ultraman Agul.
- Our Werewolves Are Different: In this case, they're alien kaiju that transform into gaseous energy when daylight arrives.
- Spring Jump: Noted by XIG for its incredible leaping power, as high as 5.7 meters and far as 7.2 meters.
- Super Speed: It possesses absurdly fast reflexes.
- First Appearance: Night of the Marionettes
- Belly Mouth: The second Psycho Mezard was shown to possess one in place of its Chest Blaster.
- Breath Weapon: They breathe lightning.
- Chest Blaster: Since this version of Mezard stands upright, it gains this ability from the normal Mezard's Backpack Cannon.
- Combat Tentacles: Like the normal Mezard.
- Eldritch Abomination: Like the original Mezard.
- Elite Mook: It's a psychic version of the first Mezard.
- Fighting a Shadow: Like the original Mezard, they begin as a spectral jellyfish-like creature that needs to be somehow pulled into our reality to be harmed.
- Flying Seafood Special: Its initial form seen hovering over whatever location it's using its psychic powers on. Has all the same abilities as the normal Mezard.
- Master of Illusion: The second Psycho Mezard uses this to plague Atsuko with visions of Lilia.
- Mind Control: The first Psycho Mezard does this to a village, creating a pseudo-zombie apocalypse scenario.
- Our Monsters Are Weird: We go from incorporeal jellyfish monsters to psychic, bipedal, incorporeal jellyfish monsters.
- Shock and Awe/Electric Jellyfish: Like the first Mezard, they can channel electricity through their tentacles.
- Technopath: The first Psycho Mezard was shown using its powers to tune into the frequencies of radios and the like to spread its mind control waves, while the second one showed the ability to disable machinery with a shower of some kind of particle.
- First Appearance: Challenge from Anti-Space
- Achilles' Heel: Destroying Antimatter's horns weakens its antimatter force field.
- Antimatter: What did you think?
- Barrier Warrior: Antimatter is permanently surrounded by a force field that turns things into antimatter. However, if an object enters without the monster's allowance, the field ruptures and the antimatter mixing mixes with matter for cataclysmic devastation.
- Eldritch Abomination: A starfish-like entity that turns all matter it comes in contact with into antimatter.
- Our Monsters Are Weird: A starfish that turns stuff into antimatter?
- Shock and Awe: Can electrify enemies it comes in contact with.
- First Appearance: When the Rain Stops
- Body Horror: These things are mutated synthetic human organs! And not to mention that humans liquified by their goop are still aware in their liquid form.
- Breath Weapon: They breathe a goop that liquifies organic materials, allowing them to slurp it up. The Mother Deents also produces a liquid with the opposite affect, allowing Gaia to restore everyone liquified by the Deents.
- Eye Beams: The Mother Deents fires one that has the same liquification ability of the normal Deents.
- Hive Queen: The Mother Deents, which is a gigantic, bloated version of the lesser Deents that spawns all the other Deents.
- King Mook: The Mother Deents is a Queen Mook.
- Mook Maker: The Mother Deents can spawn human-sized Deents by spraying a liquid from her forehead.
- Our Monsters Are Weird: Living artificial organs created by unnatural rainstorms that spew liquefying goop and are led by a queen. Yeah, definitely not a regular monster.
- First Appearance: The Birth of Agul
- Breakout Villain: Weird example. Fake Agul is one of the most popular Evil Knockoffs in the fanbase and tends to reappear in video games often, but his true form Algyuros is rarely mentioned.
- Cyclops: In its humanoid form, as it possesses a single yellow eye.
- Evil Knockoff: Transforms itself into a lookalike of Ultraman Agul to battle him. But even in its humanoid form, Algyuros sports a Colour Timer for some reason.
- Red Eyes, Take Warning: Algyuros' defining difference from Ultraman Agul in its Fake Agul form - he has pinkish-red eyes.
- Extra-ore-dinary: Since it's the second Metal Organism.
- Shapeshifter: But to a greater extent than Apatee, as not only can Algyuros become a humanoid creature and various weaponry, but a perfect duplicate of an Ultraman.
- Shapeshifter Weapon: Like Apatee, it begins the battle by morphing its arms into various weaponry, including a sword and a gun.
- Silicon-Based Life: Essentially a more advanced version of Apatee.
- Slasher Smile: After transforming into Imitation Agul, he gives off a particularly smug example.
- Spikes of Doom: Algyuros transforms itself into several of these to attack Fujimiya's hideout.
- First Appearance: Shadow of Space, Light of Earth
- Colony Drop: The organic equivalent of one,as the Radical Destruction Bringer had redirected it to collide into Earth like an asteroid.
- Living Gasbag: Not that it stops the creature from being able to collide with Earth with the same force of the asteroid that killed the dinosaurs!
- First Appearance: Shadow of Space, Light of Earth
- Back for the Finale: Is one of the Earth monsters battling the Dobishi Swarms when Zogu attacks.
- Breath Weapon: Breathes fire.
- I Love Nuclear Power: Stores huge amounts of nuclear energy in its shell. If one manages to get it to open its shell, it can then fire a massive beam of energy capable of annihilating an asteroid. However, this greatly weakens Zonnel as a result.
- Non-Malicious Monster: Zonnel is merely an animal, so it simply wants to ignore humans as long as they ignore it. For this reason Gaia spares the second one's life when he battles it in Arizona.
- Tunnel King: is a primarily subterranean monster, like most of the Earth kaiju in this series.
- Turtle Power: The shell and the Gamera-like facial features suggest this.
- First Appearance: The Fossil of Ruin
- Everything's Better with Dinosaurs: Especially if they're mutants hatched from fossilized eggs!
- Homing Lasers: Its napalm orbs have this effect, though the monster has to will them to change direction.
- Horn Attack: Shoots napalm orbs from the horn between its eyes.
- Meaningful Name: Fujimiya took it from German for "gift" because it was his "present" for destroying humans.
- Prehistoric Monster: A fossil turned into a kaiju for the specific purpose of destroying cities.
- Stock Sound Effects: The sounds its homing napalm orbs make are modified from the Poké Ball release sounds used in Pokémon!
- Ultimate Lifeform: Fujimiya mutated it to be such. Its Boss Subtitles is even "Absolute Lifeform".
- First Appearance: Sea of Mysterious Light
- Backpack Cannon: Fires lasers from the tubes on its back.
- Bioluminescence Is Cool: Produces a powerful light from the bottom of the ocean at nighttime wherever it is. These same lights also leap out of the water on occasion.
- Mega-Microbes: Candea is a mutated form of those deep-sea bacteria that can survive in the anoxic conditions of the seafloor.
- Poisonous Person: Shoots poison gas from the small tubes on its head.
- Red Eyes, Take Warning: Probably the first thing you'll spot of it when exploring the abyssal trenches it originates from.
- Sea Monster: In this case, it's a mutant form of a species of anoxic, bioluminescent bacteria from the darkest trenches of the sea.
- First Appearance: Wings of Stone
- Art Evolution: Unlike Super C.O.V., who looks the exact same as the first C.O.V., Super Pazuzu is a lighter shade of grey with a brighter red on its belly.
- Breath Weapon: Breathes fire.
- Elite Mook: Super Pazuzu, who is bigger and stronger than regular Pazuzu, with far more devastating and wide-spreading horn lighting.
- EMP: Generates so much electricity in the air around it that electronics go haywire with its presence, meaning XIG's guided missiles are completely useless against him.
- Horn Attack: It normally holds its horns straight out, but when using its lightning attacks, it curls them up.
- Meaningful Name: Derived from the Mesopotamian storm demon of the same name, befitting of the creature's electrical powers.
- Non-Malicious Monster: Revealed in its reappearance, as the monster's species hail from the same planet as C.O.V. and are peaceful there, but the Radical Destruction Bringer displaces them on Earth to let them rampage in confusion.
- Shock and Awe: Shoots lightning from its horns.
- Villain Team-Up: With Super C.O.V. in its reappearance.
- First Appearance: Gamu Expelled!
- Back for the Finale: Joins the battle to save Earth from Zogu alongside XIG and many other Earth monsters.
- Breath Weapon: Breathes fire.
- Energy Absorption: Can drain the energy of foes to sustain itself.
- Everything's Better with Dinosaurs: Strongly resembles one.
- Spell My Name with an "S": Also known as Ganemos.
- Tunnel King: Due to the fact that it spends most of its life underground, it is a powerful burrower.
- First Appearance: The Final Resolution
- Attackof The Monster Appendage: Zorlin is a Type 1, and one of the most humungous of its kind. The most we see of it is its head and neck, which is the part that Gaia battles in the climax. The rest of the monster remains hidden in the portal, but considering how its head alone is enough to swallow Gaia in one gulp...
- Breath Weapon: Breathes an enormous stream of fire. So enormous in fact, that the monster incinerates buildings with it from space.
- Early-Bird Cameo: A "small" version appears in Gamu's vision of Ultraman Gaia at the start of the series, where it battles Ultraman Gaia and foreshadows the monster's eventual arrival.
- Eat Me: Ultraman Gaia destroys Zorlim by flying into its mouth and blowing up its skull from the inside.
- Eldritch Abomination: It's a dragon-like alien so gigantic that Gaia and Agul only ever see its head and neck come out of the wormhole the Radical Destruction Bringer sent it through. If it wasn't for the resolution of the Ultras' conflict, Earth certainly would have been done for.
- The Juggernaut: Partly due to its size, but Zorlim was strong enough to survive being hit by Gaia's usual slew of abilities.
- Knight of Cerebus: Considered the most dangerous and powerful monster faced by Gaia and Agul up to that point. Matter were made worse by Gaia and Agul's rivalry climaxing in a final battle, meaning they were too occupied with each other to save Earth.
- Our Dragons Are Different: In this case, its an utterly colossal alien creature that travels through an enormous wormhole.
- Spell My Name with an "S": Also known as Zoruim.
- First Appearance: A New Battle ~Version-Up Fight!~
- A.I. Is a Crapshoot: Crisis had been corrupted by the Radical Destruction Bringer's minions the day it was built, but with the arrival of Zorlim, Crisis is finally allowed to act on its own accord.
- Battle Boomerang: Creates these from the prong-like projections on its body. The regenerate whenever they're used.
- Computer Virus: Crisis had been infected with one called Crisis Ghost created by servants of the Radical Destruction Bringer to deceive Fujimiya into believing he had to destroy humans. When Zorlim arrived on Earth, the virus goes berserk and reshapes Crisis into Meemos.
- Evil Knockoff: Initially starts off the battle as a lookalike of Ultraman Gaia. The real Gaia shows up and patches things up though.
- Extra-ore-dinary: The final Metal Organism, but unique that in it wasn't an alien lifeform, but a corrupted supercomputer.
- Extra Eyes: Whereas the previous two Metal Organisms had only one eye, Meemos has three.
- Knight of Cerebus: Its appearance reveals that Crisis was deceiving Fujimiya the whole time, marking the beginning of the second half of the series' story arc as Ultraman Agul and Fujimiya are Put on a Bus for the next while.
- Shapeshifter: Takes the information on Apatee and Algyuros in XIG's database to take on a form similar to them for battling Gaia, thus gaining their transformation abilities.
- Spell My Name with an "S": Also called Mimos.
- First Appearance: Advent of the Heat Wave
- Big Creepy-Crawlies: Based on stag beetles.
- Bilingual Bonus: Its name means "Fire Mountain", since it's as big as a mountain and has fire powers. Like Tenkai, the characters are written on its body.
- Metamorphosis Monster: While Enzan initially appears in a bell-like form similar to Tenkai, XIG's assault on it forces the creature to transform into an insectoid monster.
- Playing with Fire: Since its purpose is to melt ice, it emits an extremely intense heat from its body and can shoot fire from the characters on its chest.
- Shock and Awe: Enzan can shoot lightning from its horns.
- First Appearance: Distant City, Uqbar
- Blow You Away: Powerful winds blow to herald its appearance.
- Diabolus ex Nihilo: Like Bokurag, Rukulion is a monster who is given no allegiances with either Earth or the Radical Destruction Bringer, but given its enigmatic nature, this was probably intentional.
- Floating Continent: Supposedly hails from one, described as a utopia kept aloft by giant windmills with Rukulion as the city's guardian.
- Not-So-Imaginary Friend: Maybe. The episode leaves it open-ended on whether Rukulion and Uqbar actually exist or not.
- Our Monsters Are Weird: Befitting of the Mind Screw of an episode it appears in. It makes cymbal bangings with its footsteps, constantly beeps and whirs, and the little red thingies on its body constantly rotate. It's also implied the creature (or Uqbar) doesn't even exist, and is just the imagination of some guy obsessed with a picture from his calendar!
- Spell My Name with an "S": Also called Rukuu.
- First Appearance: The Demon's Cocoon
- Big Creepy-Crawlies: Gamu derived the name from "Gokiburi" and "Kumo", Japanese for "cockroach" and "spider" respectively, although the creature also has moth characteristics.
- Breath Weapon: Spits a foam-like substance that hardens to sticky webbing upon contact, allowing Gokigumon to build a nest or entangle foes.
- Extra Eyes: Possesses three eyes.
- Giant Flyer: Capable of soaring through space as well.
- Glowing Eyes of Doom: More readily noticed in the nighttime battle scenes.
- Non-Malicious Monster: Unlike nearly every other extraterrestrial monster in the show, Gokigumon is not a minion of the Radical Destruction Bringer and solely came to Earth to make a nest for its babies. However, XIG and Gaia still had to kill it because it was endangering human lives.
- First Appearance: The Future Seen Before
- Achilles' Heel: Destroying its horns renders it incapable of soaring through space-time.
- Breath Weapon: Spits orbs of explosive energy from its mouth.
- Giant Flyer: And a very fast one too, for that matter.
- Lightning Bruiser: A fast-moving monster with adequate strength to match.
- Non-Indicative Name: Doesn't look anything like an aerial viper, being more of a dragon-like creature.
- Super Speed: Aeroviper is insanely fast, making it almost impossible for XIG's fighter jets and even Ultraman Gaia to catch up with him.
- Time Master: Aeroviper opens up warps in space-time as it flies, entering and exiting through them to any possible timeline.
- First Appearance: Battling the Legend
- Back for the Finale: Both Shazak and its child help XIG and the Ultramen fight the forces of Zogu.
- Blow You Away: Can create great gusts of wind from its mouth.
- Breath Weapon: Breathes a beam of magma.
- Everything's Better with Dinosaurs: Invisible, porcupine-dinosaurs from Canada!
- Invisibility: Both Shazak and its child have this ability, allowing them to remain unseen indefinitely. For this reason, the local First Nations people believe Shazak to be a legendary spirit-beast.
- Non-Malicious Monster: The characters realize that Shazak merely wants to be left alone at the end of the episode when Shazak's child appears to try stop Gaia from killing its mother.
- Rolling Attack: Shazak can curl up into a ball to roll over enemies and render itself nearly invincible.
- Spell My Name with an "S": Although called Shazakku in Japanese, it's just as often translated as Syazac
- First Appearance: Crash of Souls!
- Brainwashed and Crazy: As a result of the aliens' cybernetic enhancements.
- Breath Weapon: Breathes fire.
- Cyborg: An unknown alien race captured Wolf Gas and created a cybernetically-enhanced version via a microchip on its back.
- Make My Monster Grow: The aliens transform the last surviving Wolf Fire into a giant monster after XIG manages to kill all the other ones.
- Our Werewolves Are Different: Cyborg versions of an extraterrestrial wolf-like monster.
- Playing with Fire: As its name suggests, Wolf Fire possesses pyrokinetic abilities, notably the ability to breath fire.
- Spring Jump: Capable of jumping to even greater heights and lengths than Wolf Gas.
- Super Speed: Even more than Wolf Gas.
- First Appearance: Ransom for a Monster
- Acid Attack: The egg secretes an acidic goo, which can eat through the steel body of an airplane. That was how the egg got lost by XIG.
- Breath Weapon: Breathes a heat beam.
- Everything's Better with Dinosaurs: Strongly resembles one, but is said to be more closely related to Permian mammal-like reptiles than dinosaurs.
- Make My Monster Grow: The Algona egg begins as about the same size as an ostrich egg, but throughout the episode, it grows and grows until it reaches kaiju size and hatches out the monster as an adult.
- Non-Malicious Monster: Algona is a mild creature most of the time and was rampaging because it was confused upon hatching. This, as well as the creature's value to science, means Gaia simply freezes the monster to preserve it.
- Prehistoric Monster: Was preserved in Antarctic ice as an egg for millions of years.
- Red Eyes, Take Warning: Has little bright red eyes.
- Stock Sound Effects: Algona's roar is one of several stock roars created by veteran American voice actor Frank Welker for various cartoons.
- First Appearance: The Sky of Reunion
- Doppelgänger Attack: X-Savarga summons copies of itself to attack Gaia during the battle. The copies also possess their own Mook Maker abilities.
- Healing Factor: Regenerates one of its hands when XIG blows it off.
- Mook Maker: X-Savarga's right palm launches tiny versions of itself that latch themselves to Ultraman Gaia and begin to electrocute him before exploding. Worse still, they also drain a great deal of his Colour Timer energy.
- Action Bomb: The mini X-Savargas explode after a few seconds, causing massive damage to Ultraman Gaia.
- Energy Absorption: The mini X-Savargas do this as they latch onto Gaia.
- Shock and Awe: The mini X-Savargas channel massive amounts of electricity through their bodies, shocking Ultraman Gaia before they explode.
- Right Hand of Doom: X-Savarga's left hand is a giant drill.
- Spell My Name with an "S": Also called X Sabaga.
- This Is a Drill: Its Right Hand of Doom.
- First Appearance: Fourth Symphony of a NightmareVoiced by: Makiko Kuno
- Belly Mouth: Possesses a smiling face on her torso.
- Combat Tentacles: Possesses two whip-like tentacles in her true form.
- Eldritch Abomination: Even more so than all the Mezards before her. She's a highly intelligent creature with incredibly potent psychic powers, a devil-like nature, and a human-like face on her torso. She's also the only one not seen in projection form though.
- Extra Eyes: Has six eyes (eight, if you count the two on her torso's face).
- God Save Us from the Queen!: The queen of a species of interdimensional jellyfish kaiju is every bit as malevolent as she sounds.
- The Man Behind the Man: She created the Crisis Ghost, infecting the Crisis supercomputer to become an agent of the Radical Destruction Bringer and eventually transform into Meemos.
- Manipulative Bitch: She was the one who initially led Fujimiya to believe Humans Are Bastards, and she tries to lure him back into the idea again by taking the form of one of his deceased and dearest friends.
- Master of Illusion: Like Psycho Mezard. This time, she uses her abilities to create an image of Dr. Inamori to speak to Fujimiya. She even creates a hallucination of Ultraman Agul (called Shadow Agul to differentiate it from Algyuros's Fake Agul) to attack Gaia and XIG!
- Mind Control: She takes over the Kanto Community Broadcasting building using this.
- Monster Lord: She's one of the most important minions of the Radical Destruction Bringer, as she commands all the lesser Mezards.
- Shock and Awe/Electric Jellyfish: Like the previous Mezards.
- Technopath: Like the Psycho Mezards, she can transmit her mind control waves through devices such as phones and computers to spread them further.
- First Appearance: Ground-Breaking Tusks
- Back for the Finale: Alongside Geel, Shazak and Mizunoenoryu, the third Tigris appears to fight the forces of Zogu.
- Breath Weapon: Breathes orbs of magma.
- Butt-Monkey: Tigris dies THREE times, first succumbing to the wounds from the underground nuclear test, then getting killed by Blitz Blots, and then it gets killed by the Dobishi swarms. For the god of the earth, that's kinda embarrassing.
- Dishing Out Dirt: As the god of the land.
- Non-Malicious Monster: Like Mizunoenoryu, Shazak and Geel, Tigris is the protector of its realm. When it helps Gaia battle Blitz Blots, XIG realizes that Tigris opposes the forces of the Radical Destruction Bringer as much as the humans and Ultramen do, which leads to them accepting the Earth kaiju as allies.
- Panthera Awesome: A tiger god, though it takes cues from sabertooth cats and Chinese lions as well.
- Tragic Monster: Tigris is so horribly wounded by GUARD's nuclear testing that Ultraman Gaia and most of XIG refuse to kill it, seeing the monster vomiting blood and shambling pathetically. These is little celebration when Tigris' misery comes to an end, though it is reborn later on.
- Tunnel King: Since it's the god of earth, Tigris is a powerful burrower.
- First Appearance: The Lake of SadnessPlayed by: Hiroyuki Okano (as Kondo)
- Combat Tentacles: Tsuchikera uses its tentacles to snatch trespassers from the safety of the lake.
- Expy: Inspired by Jamila from the original Ultraman.
- Go Out with a Smile: Gaia ends Tsuchikera's suffering by reducing him to particles of light. Kondo then appears one last time in front of Hirano, thanking him for everything he had done before vanishing forever.
- Music Soothes the Savage Beast: Hirano would play Chie's music box to keep Tsuchikera from completely losing his humanity and to calm him down when he got too aggressive towards trespassers.
- Nuclear Nasty: The underground nuclear testing that injured Tigris leaks into his lake, turning him into a kaiju and driving him into permanent madness. However, it's also slowly killing him.
- Sanity Slippage: The nuclear material from the previous episode causes this for Kondo, making him more aggressive. Fortunately, he regains his humanity at the end of the episode.
- Tragic Monster: AND HOW! Tsuchikera's episode will leave you in tears. This guy Was Once a Man, but became an abomination due to human cruelty and was only able to maintain his sanity through his friendship with Hirano and the love of his daughter Chie, only to go off the brink when nuclear testing turns him into a kaiju.
- Was Once a Man: Used to be a single father and Pacific War biological warfare scientist named Kondo.
- What Measure Is a Non-Human?: Hirano becomes offended by Gamu calling Kondo a monster, preferring to refer to Tsuchikera as his friend.
- First Appearance: I Want to See Gaia!
- Breath Weapon: Spits energy bombs.
- Cephalothorax: Pazgeek's "body" is pretty much just a head (or the reasonable equivalent of one) with pincers and legs.
- Extra Eyes: Those four blue things on its...pointy...part...? Those are its eyes.
- Our Monsters Are Weird: Seriously, just look at that thing! This guy probably takes the cake for bizarre Ultraman Gaia monsters because it really cannot be described with words alone.
- Spell My Name with an "S": Pazgeek or Tazgeek?
- First Appearance: The Resurrection of Agul
- An Arm and a Leg: Ultraman Agul tears off Sigma-Zuigul's "wings" (the ring-like projections growing from its sides; they fold up when not in use) to prevent the monster from going back through its wormhole to M91.
- Cyber Cyclops: Has a single red eye.
- Hand Blast: Able to fire energy missiles from its fingers.
- Humongous Mecha: A giant alien robot sent by the Radical Destruction Bringer. However, its Boss Subtitles "Space Capture Mecha-Beast" suggests that it may actually be more of a Mechanical Lifeform instead.
- Knight of Cerebus: It is with Sigma-Zuigul's appearance does the final story arc begin, as the Radical Destruction Bringer begins to send its most powerful minions to destroy Ultraman Gaia and Agul.
- Mechanical Monster: Far less humanoid than a typical giant robot and implied to be more of a lifeform than an artificial being.
- Power Nullifier: In order to capture Gamu, Sigma-Zuigul fires a beam of energy from its cross-shaped cell that locks the Esplender in a metal casing, preventing Gamu from turning into Ultraman Gaia before trapping him inside a metal cross. It also manages to fire one at Ultraman Gaia at the start of the episode, preventing the hero from using his Finishing Moves.
- Pulling Themselves Together: Ultraman Gaia actually destroys Sigma-Zuigul in their first battle, but the robot rematerializes from thousands of tiny pieces and catches Gamu off-guard, crucifying him.
- Red Eyes, Take Warning: Possesses a single red eye.
- Tractor Beam: Uses this to crucify Gamu inside a small cell within its body.
- First Appearance: Ultraman Tiga, Ultraman Dyna, & Ultraman Gaia: Battle for Hyperspace, Gamu vs. Gamu (in series)Voiced by: Daisuke Gori (movie only)
- Arm Cannon: has organic laser cannons on its wrists.
- The Blank: Like Bizorm, Satanbizor has no face, only a glowing yellow patch that shoots lasers.
- Early-Bird Cameo: Appears in the opening sequence of the crossover movie Ultraman Tiga & Ultraman Dyna & Ultraman Gaia: The Battle In Hyperspace on a television show, and is later seen battling Ultraman Gaia when the hero first appears.
- Energy Being: Satanbizor's normal form, being a Spirit Parasite, until it manages to steal DNA or merge with a human.
- Shapeshifter: As a Spirit Parasite, Satanbizor can take the DNA of humans to transform himself into a particular individual. In this case, he takes that of Gamu from when he was crucified by Sigma-Zuigul.
- We Hardly Knew Ye: Both of his appearances are incredibly brief and end with Satanbizor being killed, as he only appears in a nightmare sequence in the show, while its movie appearance is merely to establish Gaia himself.
- Wolverine Claws: Equipped with two retractable examples on each hand.
- First Appearance: Gamu vs. GamuVoiced by: Albert Smith (also Klaus' actor)
- Asteroids Monster: Cutting Bizorm into pieces causes him to turn into lots of small Bizorms that can re-merge into a singular Bizorm again.
- Blade Below the Shoulder: Can create a blade of energy from his right hand.
- The Blank: Has only yellow patch on his face, intentionally reminiscent of Zetton and Kyrieloid.
- Chest Blaster: Can fire a yellow laser from the glowing patches on his chest and face.
- Deal with the Devil: Klaus Eckhart made one with the Spirit Parasites in order to be able to serve the Radical Destruction Bringer, transforming into Bizorm.
- Evil Counterpart: As the title of the episode suggests, Klaus and Gamu are very similar in many ways. Both were insecure about how as members of Alchemy Stars, people treated them differently for their genius intellect, so they sought comfort by turning towards more powerful entities. But whereas Gamu turned to the benevolent Ultraman Gaia to protect Earth to conquer his fear, Klaus fell for it and chose the Radical Destruction Bringer to become even greater.
- The Man Behind the Man: Klaus had placed a transmission diode in Sigma-Zuigul so when the robot captured Gamu, his XIG-NAVI would be infected to allow Satanbizor to visit Gamu in his dreams and lure him to Germany.
- The Mole: Although a member of Alchemy Stars, he was actually in service of the Radical Destruction Bringer after the Crisis supercomputer revealed the threat of humans to him and Fujimiya.
- Was Once a Man: Used to be a German Alchemy Stars member until he was swayed to the side of the Radical Destruction Bringer as he believed humans should embrace its power to become greater. He became Bizorm by merging with the Spirit Parasites.
- First Appearance: The Silver Eyes of Izac
- Alas, Poor Villain: Izac suffered from intense pain when being transformed into a kaiju by the Radical Destruction Bringer, and Gamu and Fujimiya were reluctant about killing it. Gamu shows a great sympathy for Izac afterwards.Gamu: I could also hear Izac's voice. Izac was born on this Earth, and all he wanted was to live on this planet. But I...Fujimiya: You know it wasn't you who slew Izac. We humans, who made the Artes Tigers extinct, slew him. Gamu, you once said, that humans could change. I want to believe that. But, unless man shoulders the pain of their errors from the past, they cannot truly change.
- Breath Weapon: Breathes fire.
- Glowing Eyes of Doom: Its eponymous "silver eyes", the only feature seen of the animal in its unmutated form.
- Last of His Kind: Izac is a clone of the very last Artes Tiger known to science.
- Lightning Bruiser: Izac is incredibly swift and strong, so much that it overwhelmed Ultraman Agul when they fought each other. It even manages to give Ultraman Gaia a hard time in his Supreme Form.
- Madness Mantra: When Gamu hears the monster's thoughts, he hears only "I will survive, Gaia.", as the creature still retains its Earthly animal instinct.
- Panthera Awesome: A mutant tiger kaiju, although he also has a mane like a lion.
- Spell My Name with an "S": Izac or Izak?
- Spring Jump: Since its a tiger, Izac can still pounce, and due to now being a kaiju, it can pounce very high into the air.
- In a Single Bound: Not only is Izac able to jump a thousand feet into the air, but can pounce at a length of a thousand feet.
- Super Speed: Can run so fast not even Gaia's Supreme Mode was able to counter it.
- Tragic Monster: A kaiju developed from an animal driven to extinction by humans, only to be transformed into a horrible monster by evil forces, forcing the humans to (this time, reluctantly) make it extinct again.
- First Appearance: The Living Planet
- Achilles' Heel: Blitz Blots' Attack Reflector may be it's most powerful tool, but it's also the monster's most vulnerable, as too much energy being absorbed can damage it, as can a large amount of human firepower.
- Arm Cannon: Is equipped with organic wrist cannons that shoot explosive orbs of fiery energy at foes.
- Attack Reflector: Blitz Blots has an orb-like structure in its chest that catches energy beams and shoots them back at enemies.
- Giant Flyer: Bird-man kaiju. Able to fly at Mach 9.
- The Juggernaut: Blitz Blots is one of Ultraman Gaia's toughest foes, thanks to his natural strength and Attack Reflector, which forced Gaia, Tigris, Team Hercules, and Team Lightning to all work together to overpower the monster. He even manages to defeat Ultraman Agul in the first round of combat by catching the blue Ultraman off-guard with its abilities.
- Our Monsters Are Weird: He's rather tame compared to some examples from this show, but a black-and-white bird-man that can catch energy beams with its chest and shoot them back at foes is definitely not a normal kaiju.
- Spell My Name with an "S": Also called Blitzblotz, Blitzblots, or Blitz Blotz.
- Winged Humanoid: Modeled after a Tengu. The wings turn into a pair of shoulder spikes when the monster uses its Attack Reflector to assist in the absorption and redirection of energy.
- First Appearance: Attack of the Forest
- Bilingual Bonus: Like Enzan and Tenkai, Shinryoku has kanji on its body. They read "Deep Green", in reference to its Green Thumb powers.
- Blinded by the Light: Can create fire orbs that create powerful flashes of light.
- Cyclops: Possesses a single "eye".
- Demonic Possession: Takes over the body of the head of the Radical Destruction Bringer cult, Yabuki Shiroigai, in order to speak to Gamu.
- Green Thumb: As its purpose is to replant forests, it can make trees and plants sprout from the ground, so much that it completely smothered Tokyo in trees.
- Hand Blast: Can shoot energy bolts from its fingers.
- It Can Think: Unlike Enzan and Tenkai, who were like mindless machines, Shinryoku is fully sentient. However, since it can't really communicate with people in its normal form, it just takes over the body of Yabuki Shiroigai to tell Gamu about the Nature Control Machines' goal to "purify" Earth for the Radical Destruction Bringer.
- The Man Behind the Man: As Shinryoku explains in the body of Yabuki, it sent Tenkai and Enzan to cleanse Earth for the Radical Destruction Bringer before deciding to carry out the job by itself.
- Meaningful Name: Derived from the Japanese word for "invasion" — "shinryaku", indicating its relationship with the alien forces of the Radical Destruction Bringer.
- Metamorphosis Monster: Like Enzan, Shinryoku appears in the form of a giant bell when it first lands on Earth, leading everyone to assume it's a strange alien structure. However, when Shinryoku leaves the body of Yabuki, the building comes to life as Shinryoku's true form, growing legs before revealing the rest of its form.
- Our Monsters Are Weird: A giant bell with limbs that create trees?
- Power Nullifier: Inside Shinryoku's body is a control system that produces a field that prevents Gamu from becoming Ultraman Gaia, allowing Shinryoku to capture him and speak through Yabuki Shiroirgai's body.
- Shock and Awe: Can conjure electrocuting vines from the ground to entangle Gamu and later Ultraman Gaia.
- First Appearance: XIG Destroyed!
- Colony Drop: Shinigami's scheme was to crash his planetoid-like Living Ship into Earth and cause a mass extinction primarily aimed at humanity.
- Combat Tentacles: If its organic cannons are destroyed, Mokian creates tentacles to grab its enemies.
- Cyclops: Has a single orange eye.
- Eye Beams: Shoots fireballs from its single eye.
- Eyes Do Not Belong There: Its only eye is located inside its mouth.
- Living Ship: Of Shinigami, complete with wings and organic laser cannons. He also holds Fujiiya and Reiko inside to speak with them while Mokian moves towards Earth.
- Number of the Beast: Mokian is 333 meters in circumference and weighs 330 thousand tons, in reference to the infamous 666.
- Phantom Zone: The Womb of Mokian, a pocket dimension inside the monster where Shinigami speaks to Reiko and Fujimiya.
- Shock and Awe: Mokian can deliver electric shock to anything it makes contact with, mainly through its Combat Tentacles.
- Taking You with Me: Its purpose was to crash itself into Earth like a kamikaze. However, it gets taken out by similar methods, with Commander Ishimuro flying the Aerial Base into the monster, successfully destroying it (Gaia manages to rescue him in time).
Shinigami / Zebub
- First Appearance: XIG Destroyed!Voiced by: Masami Horiuchi (also Shinigami's suit actor)
- Achilles' Heel: His eyes are the source of his force field while his horns provide his lightning powers, so destroying them weakens him greatly.
- Barrier Warrior: Zebub can create an electromagnetic force field around himself.
- Blade Below the Shoulder: Has one as his Right Hand of Doom.
- Energy Absorption: The crystal on his forehead allows him to perform this on Ultras' beam attacks or their Colour Timer energy.
- Eye Scream: In order to disrupt his barrier powers for Ultraman Gaia and Agul, XIG blows out one of Zebub's eyes.
- A God Am I: Shinigami believes this, explaining to Fujimiya and Reiko as why the Radical Destruction Bringer has decided to destroy Earth. Reiko is quick to point out that he has no right to judge the fate of the planet, but Shinigami doesn't listen.
- Hand Blast: Can shoot energy bolts from his hands.
- Herald / The Dragon: Of Zogu and/or the Radical Destruction Bringer (see below for details).
- Hypocrite: Claims humanity are a virus that's bringing suffering to the universe and should be wiped out for its sake. Reiko calls him and his master out as complete hypocrites who use a facade of good intentions to excuse wanting to destroy humanity out of nothing but hatred, as well as so far causing more suffering than humanity has.
- The Man Behind the Man: Claims to have created Apatee and Algyuros to test the power of Ultraman Gaia and Agul respectively.
- Manipulative Bastard: Like Queen Mezard, Shinigami tries to sway Fujimiya to turn his back on humanity once more, except explicitly stating that he should serve the Radical Destruction Bringer.
- Names to Run Away from Really Fast: Shinigami means "Death God" in Japanese, while Zebub is derived from the Christian demon Beelzebub. Their Boss Subtitles would also count — Shinigami's is "Death God", while Zebub's is "Destruction Devil".
- Ominous Owl: Zebub's motif, since owls are popularly associated with death, befitting of the true form of the "Death God".
- One-Winged Angel: Zebub, which is the true form of Shinigami that he turns into to battle Gaia and Agul.
- Power Crystal: A small one on his forehead that can steal energy.
- Power Floats: Shinigami perpetually levitates in a sitting position.
- Right Hand of Doom: Has a massive sword in place of his right hand, which he uses to brutally stab Ultraman Agul with during their fight.
- Shock and Awe: Can shoot lightning from his hands and forehead.
Dobishi / Kaiser Dobishi
- First Appearance: An Angel Descends
- Blade Below the Shoulder: Kaiser Dobishi can form a sickle on their arms.
- Cephalothorax: The Kaiser Dobishi have a single eye on their chest and a mouth on their belly.
- Death by a Thousand Cuts: The Dobishi manage to overwhelm the Earth defenders with their sheer numbers. Geel and Tigris succumb, while Zonnel is almost killed until the American XIG team intervenes.
- Eye Beams: The Kaiser Dobisihi fire them from their chest and knees.
- Eyes Do Not Belong There: They have additional eyes on their knees!
- Herald: Of Zogu/the Radical Destruction Bringer (see below for details).
- Horde of Alien Locusts: They're like Biblical locusts from space.
- Insectoid Aliens: Like most minions of the Radical Destruction Bringer, the Dobishi hail from the M91 Galaxy.
- Overly Long Tongue: Kaiser Dobishi are equipped with these, which they use like ropes to construct the Ultramen.
- Razor Wings: Dobishi have these
- The Swarm: They completely darken the Earth's skies as millions pour from Zogu's wormhole and overwhelm the Ultramen, XIG, and the Earth kaiju. And of course, since there's so many of them, Gaia and Agul have to fight dozens of Kaiser Dobishi.
- Worm That Walks: Kaiser Dobishi are composed of thousands of lesser Dobishi.
- First Appearance: An Angel DescendsVoiced by: Motoko Nagino (also Angel Form's suit actor)
- Beware the Superman: Zogu's is the Radical Destruction Bringer's most powerful enforcer and her stature easily dwarfs Gaia and Agul, and subsequently making short work of them with little to no effort at all before driving humanity into the brink of despair.
- Big Bad: Assuming that she is not a minion of the Radical Destruction Bringer. However, due to the intangible nature of the Radical Destruction Bringer, many fans believed Zogu was supposed to be the Radical Destruction Bringer until better information discarded that.
- David vs. Goliath: With the Ultramen being the David. She literally swats them out of the sky like flies in the final battle.
- Dragon-in-Chief: Due to the vague nature of the Radical Destruction Bringer.
- Eldritch Abomination: An absolutely gargantuan alien being that takes on the form of an angel and serves an enigmatic godlike entity.
- Energy Absorption: Was able to drain Ultraman Gaia and Agul's energy after defeating them.
- Giant Foot of Stomping: Given her size, she is capable of doing this to Ultras.
- A God Am I: XIG observes that she takes on the form of an angel because she believes that she has the right to judge and destroy the human race like a god would.
- Hand Blast: She shoots beams of devastating light from her hands and can also create an enormous shockwave orb that sends Gaia and Agul flying for several city blocks.
- The Juggernaut: She completely devastates Gaia and Agul with her powers and enormous size. Even Mizunoenoryu, the God of Water, is unable to do much against her.
- Light Is Not Good: Her angel form is enveloped in bright light, and the characters initially assume she's here to help Gaia and Agul as she kills some Kaiser Dobishi and uses her light to replenish their Color Timers. Then, she completely pummels them and XIG realizes who they're really facing.
- Number of the Beast: Her second form is 666 meters tall and 660 thousand tons.
- One-Winged Angel: For the final battle, Zogu transforms into an even more gigantic demon-like form (her true form) capable of crushing a skyscraper with its feet.
- Our Angels Are Different: Well, she's an incredibly gargantuan and malevolent alien entity that merely takes the form of an angel to demonstrate her belief that she on par with a divine being.
- Our Demons Are Different: However when Gaia and Agul start putting up a fight she drops all pretense and transforms into her true form which resembles more of a vaguely centaur-like demon.
- Satanic Archetype: Has the hallmarks of one predating Ultraman Belial. Let's see, her first form is a malevolent angel sent to destroy humanity invoking Light Is Not Good. Then, her second form is a centaur-like dragon, and the fact that she stands at 666 meters tall in that form doesn't help matters either.
- Villainous Breakdown / The Berserker: When Zogu takes her true form, she has no more need to be pragmatic, and simply begins destroying everything in sight using her drastically-more powerful abilities.
- First Appearance: Ultraman Gaia: Once Again Gaia
- First Appearance: Ultraman Gaia: Once Again Gaia
- First Appearance: Ultraman Gaia: Once Again GaiaPlayed by: Jasmine Marika (Melissa)
- Voiced by: Nana Yamaguchi, Mai Saito (as Lisa)
- Anti-Villain: Despite its world-breaking power and being infinitely destructive in potential, the Red Sphere itself is aware of this and wants to find somebody who could use it for good.
- Big Bad: Of Ultraman Gaia: The Battle In Hyperspace.
- Death Seeker: Ultimately sought for somebody to wish for it to disappear so it could never be used for evil again.
- Expy: Based on the living wishing stone that appeared in the original Ultraman which ended up creating the monster Gyango.
- MacGuffin Turned Human: Turns out to have a human interface in Lisa, a new girl at Tsutomu's school that he befriends.
King of Mons
- Barrier Warrior: Can use its wings to create a powerful force field capable of even blocking the Photon Edge.
- Belly Mouth: Possesses a vertical set of gnashing teeth on its belly that allow it grab foes up close.
- Breath Weapon: Breathes a beam of red energy that then generates a series of massive explosions.
- Exactly What It Says on the Tin: King of Mons is the King of Monsters, commanding two lesser kaijus.
- Extra Eyes: Has three red eyes.
- Land, Sea, Sky: Represents Land, while his miions represents sea and sky.
- Mook Maker: Spawns Bajiris and Scylla from its own body.
- Super Strength: It was literally created to be the strongest monster ever, so this comes naturally.
- Synchronization: Fatally injuring Bajiris and Scylla will severely weaken King of Mons, proving to be enough for Gaia to finish him off alone.
- Big Creepy-Crawlies: Loosely modeled after insects, primarily mantises
- Blade Below the Shoulder: Is equipped with curved blades in place of arms, which it can put together like a pair of scissors to slice up enemies.
- Breath Weapon: Breathes explosive red orbs of energy.
- Co-Dragons: One of the two monster servants of the King of Mons.
- Giant Flyer: Bajiris' bony wings allow it to fly through both sky and space with swiftness.
- Land, Sea, Sky: Represents sky, where it fights Ultraman Dyna in the stratosphere.
- Shared Life Meter: Shares it's life with King of Mons.
- Body Horror: Scylla's jawline actually extends all the way back to its dorsal fin, so when it opens its mouth the whole upper half of the creature's front is entirely lifted into the air!
- Co-Dragons: One of the two monster servants of the King of Mons.
- Land, Sea, Sky: Represents sea, where it fights Ultraman Tiga underwater.
- Meaningful Name: After a multi-headed sea monster from Greek mythology.
- Sea Monster: Although it only enters the water during the final stages of the battle, Scylla's name and appearance shows it is at home in the sea.
- Shared Life Meter: Shares it's life with King of Mons.