* BizarroEpisode: Episode 29 "Distant City, Uqbar" is one serious MindScrew.
* CompleteMonster:
** [[EldritchAbomination The Radical Destruction Bringer]] is an entity from deep space bent on the [[KillAllHumans annihilation of the human race]]. Claiming to be saving the Earth and universe by destroying humanity to trick Hiroya Fujimiya into helping it, [[NotSoWellIntentionedExtremist in actuality]] its only motive for seeking humanity's destruction is a God complex and hatred of beings it sees as "insects on a trash heap". In the course of its rampage, among other atrocities, it would exploit innocent {{kaiju}} from both Earth and space and send them to their deaths without remorse; brainwash entire cities into rabid zombies; attempt to send an entire region of Japan into the Earth's mantle; and try to cause the tectonic plates to rip themselves apart under humanity's feet. In the end, it would send its Dobishi army to destroy humanity via blotting out the sun and letting them freeze to death in the cold, alongside its enforcer, the Root of Destruction, [[DragonInChief Zogu]]. When Earth's monsters rise against it, the Destruction Bringer shows them no mercy and has its Dobishi brutally kill many of them without remorse. Despite its claims of benevolence, the Destruction Bringer is nothing more than a self-righteous hypocrite motivated by hate.
** The aforementioned [[DragonInChief Zogu]] ("Fundamental Destruction Angel") is one of two Roots of Destruction, the Destruction Bringer's [[CoDragons strongest enforcers]]. Sent to Earth alongside the Dobishi to destroy all life on Earth, Zogu has the Dobishi block all communications except for the news media so humanity can watch the increasingly hopeless situation unfold and [[HopeCrusher fall into despair]]. When Gaia and Agul arrive to stop them, Zogu descends while [[BitchInSheepsClothing feigning benevolence]] and atomizing three of her own Kaizer Dobishi. She then reveals her true colors by brutally pummeling the two into submission with sadistic glee before draining their power and revealing to the world their true identities as mere humans. Zogu then falls back to allow her Dobishi to blot out the sun and watch humanity slowly die in cold and despair. When Earth's monsters rise up against her, she has the Dobishi attempt to brutally kill them. When Gaia and Agul manage to return and harm her, Zogu reveals her [[OneWingedAngel demonic true form]] and attempts to crush the two to death. While an enforcer of the Destruction Bringer's will, the joy in which Zogu does so makes her just as bad as her master.
** ''Film/UltramanGaiaOnceAgainGaia'': [[BigBad Gakuzom]] ("Root of Destruction Sea God") is Zogu's [[TheBrute brutish]] fellow Root of Destruction. Surviving Zogu's defeat and his master's retreat, [[DragonAscendant Gakuzom would begin his own onslaught]] on Earth several years later. Attacking the peaceful and defenseless Rinar 8,000 feet below, Gakuzom would viciously assault the GUARD sub sent to answer their SOS. Finally making his move and plunging the Pacific into a perpetual storm, Gakuzom attempts to [[OmnicidalManiac wipe out all life on Earth]] with his Baiakuhe, with the Root of Destruction attacking Tokyo personally. When Agul arrives to stop him, Gakuzom has his minions maul and restrain the hero while he beats him down himself. When Gaia arrives, Gakuzom [[BadBoss devours his entire army]] and begins brutally pounding the two heroes.
* CreepyCute: Despite being an EldritchAbomination {{Oculothorax}} resembling a walking mass of eyes and muscle, Gan Q has incited this reaction in some fans due to his simple, child-like design and high-pitched giggling.
* EnsembleDarkhorse:
** Ultraman Agul and by extension, Fujimiya. In fact, the two were supposed to be retired when Gaia obtains Agul's power but the sheer amount of PopularityPower allows them to return.
** Gan Q for the series' monsters. He ranks up with the likes of [[Series/{{Ultraman}} Gomora, Baltan, Pigmon, and Dada]] in sheer recognizability amongst Ultra monsters.
** The series has more recurring non-Japanese characters than any other Japan-produced Franchise/UltraSeries, so not surprisingly, they've nabbed quite a bit of attention amongst western fans.
* FanPreferredCouple: [[TheHero Gamu]] and [[BridgeBunnies Ats]][[{{Tsundere}} uko]]. The fact that their relationship never resolves by the end is a major disappointment amongst fans.
* SugarWiki/FunnyMoments:
** Episode 12 has Gamu and Team Lightning chase after Wolf Gas on foot. It's revealed that Team Lightning is far less competent outside of their XIG fighters; Kitada and Ogawara get taken out easily, and despite being the leader of a fighter squad, Kajio ''sucks'' at shooting. In the morning, Chief Tsutsumi found the four of them sprawled out across the floor completely exhausted, with Gamu looking like he's about to throw up at any moment.
** The ''entirety'' of episode 35 "Ransom for a Monster". A group of DumbCrooks find the MonsterOfTheWeek's egg and decide to hold it for ransom, pretending to be aliens. They accomplish this by barely changing the name of the iron working company they work for. The funniest part is GUARD plays the entire situation completely straight, unaware it's a scam.
* HarsherInHindsight:
** Episode 33 shows an alternate future wherein Team Falcon made a HeroicSacrifice by killing Aeroviper at the cost of their lives. In real life, one of the actors of Team Falcon, Shogo Shiotani, [[DrivenToSuicide committed suicide]] in 2002.
** In the same vein, Commander Ishimuro attempting a HeroicSacrifice in episode 47 [[spoiler:by ramming the Aerial Base into Mokian]] is harder to watch after his actor Hiroyuki Watanabe committed suicide in 2022. Even more so, Watanabe is the ''second'' actor playing a commander role in an ''Ultraman'' show who committed suicide. The first is Minoru Tanaka, who appeared in ''Series/UltramanMebius'' as Captain Sakomizu.
** The 2018 sequel novel to ''Film/UltramanGaiaTheBattleInHyperspace'' titled, ''Adventure in Hyperspace'' has the [[https://ultra.fandom.com/wiki/Shunsuke_Kuji main antagonist]] using his monster to destroy a television studio and his toy company after assuming those two cheated him of his winning prize comes a lot more terrifying when a year later, an arsonist burned the animation studio Kyoto Animation under the assumption that the studio stole the ideas from his rejected novel submissions.
* HeartwarmingInHindsight: One of Gamu's dream and idea is that he wished to not fight the monsters that he faced. Later in the franchise, his successors Series/UltramanCosmos and Series/UltramanX not only avoid engaging in brutal fights but also tame and make peace with the monsters that they face, making Gamu's dream come true.
* HilariousInHindsight:
** Creator/ChiakiKonaka [[Anime/DigimonTamers goes into Kaiju-writing business again three years later.]]
** Georgie’s part of the RousingSpeech to Gamu and Fujimiya is saying that if they die, then she’ll have to become “Ultrawoman”. Over two decades later, Georgie’s actress Maria Theresa Gow voiced Ultrawoman Beth in Series/UltraGalaxyFightTheDestinedCrossroad, making her statement prophetically true.
** A team of [[Anime/YuGiOh5Ds Riding Duelists in the WRGP]] are also named "Team Lightning".
** A heroic persona directly created by the Earth itself to oppose the encroaching evil? Are you sure we are not talking about [[Anime/HealinGoodPrettyCure Cure Earth]] instead?
* MemeticMutation: See the [[Memes/UltraSeries Franchise page]].
* MisaimedFandom: There are fans who agree with Fujimiya's view that HumansAreBastards and think that he is right in regarding humans as the ones to be eliminated if Earth is to survive. In the show itself, Fujimiya's ideology, whilst given weight, was consistently refuted and disproven by the actions of Gamu, Reiko, [[JerkWithAHeartOfGold himself]] and many other characters [[spoiler:and was revealed to be due to manipulation from the Radical Destruction Bringer. After his return, Fujimiya opts to give humans a chance instead]].
* {{Narm}}: Geschenk's roar, which also combines a cat's meows.
* OlderThanTheyThink: Whilst Agul is the first ''canonical'' blue-coloured Ultra, he is not the first blue Ultra in history; that honour goes to [[https://ultra.fandom.com/wiki/Evil_Ultraman_Great Ultraman Great's evil counterpart]], and the first instance of a blue Ultra licensed by Tsuburaya would be the little-known [[https://ultra.fandom.com/wiki/Ultraman_Kiyotaka Ultraman Kiyotaka]].
* RetroactiveRecognition: Some of the series' cast would later go on to play roles in the ''Franchise/KamenRider'' series:
** Hassei Takano (Hiroya Fujimiya) would later go on to play Miyuki Tezuka/Kamen Rider Raia in ''Series/KamenRiderRyuki'', and then the reboot version of [[Series/KamenRider Hayato Ichimonji]] in ''Film/KamenRiderTheFirst'' and its sequel, ''Film/KamenRiderTheNext''.
** Hiroyuki Watanabe (Commander Akio Ishimuro) portrayed Gaoh, the BigBad of ''Series/KamenRiderDenO: I'm Born'' and is also widely recognized for the character of Taiga Samejima in the ''Series/{{GARO}}'' franchise.
** Maria Theresa Gow (Georgie Leland) makes a guest appearance in episodes 47 and 48 of ''[[Series/KamenRiderDouble Kamen Rider W]]'' as Neon Ulsland, an executive of Foundation X.
** Takashi Ukaji (Chief Tsutsumi) portrays Chairman Kousei Kougami in ''Series/KamenRiderOOO''.
* TearJerker: Tsuchikera's episode "The Lake of Sadness" is one of the biggest in the Ultra series.
-->'''Kondo:''' Thank, you, Hirano. Because you were there for me, I managed not to lose my heart. Now I'm ready to go to where Chie is. Thank you, Hirano.
* TheyWastedAPerfectlyGoodPlot: The relationship between Gamu and Atsuko is this towards most fans, since they never had a resolution in the end despite a lot of plot buildup in-between them. Such examples can be shown on their similarly FriendlessBackground, Atsuko growing from a {{Tsundere}} towards a more warming personality to Gamu and a minor ClingyJealousGirl moment in episode 42. The OV (taking place sometime after final) has Gamu resuming his life as a university student and Atsuko returns to her Tsundere mode again.
* UnfortunateCharacterDesign: The [[https://static.wikia.nocookie.net/ultra/images/7/70/555fbb589e2df45b7f15f64ae1d1af97.jpg/revision/latest?cb=20140409072154 combined form of Crabgan and Anemos]] places Anemos' mouth between the suit actor's legs, giving it a phallic appearance.