* AntiClimaxBoss: Most of the monsters were defeated very quickly when they appear. The challenge in most episodes is in actually finding them. [[spoiler: This includes the final boss, which is actually [[TheSwarm a large group of subterranean giant insects.]] Once his consciousness awakens, Seven proceeds to destroy them in less than 5 minutes. Justified, as Seven is an OutsideContextProblem and the native alien invaders are less prepared for dealing with him than is normally the case.]]
* CompleteMonster: [[TheWormThatWalks Peginera]] ("[[PuppeteerParasite Parasitic Space Creature]]"), from episode 4 ""DIAMOND "S"", is one of the worst alien invaders ever investigated by DEUS. Desiring to adapt to Earth's atmosphere with a new body that would allow it to conquer the planet, Peginera splits its own cells into countless parasites and takes over the entire staff of Nano Cybertech, [[MedicationTampering tainting their most popular product]] with its cells to infect thousands more, even [[WouldHurtAChild children]]. Those who refused to submit to the HiveMind have their bodies turned into mummified husks, with Peginera itself coldly seeing this horrible demise as a form of punishment. A sadistic, cruel being that managed to stand out in one of the darkest installments of the franchise, Peginera wasted no time in causing destruction once it finally got a body.
* FridgeBrilliance: TheReveal that [[spoiler:Ultraseven X ''is'' the original Ultraseven makes the frequent {{Curbstomp Battle}}s make sense. He's from an alternate universe, in this one he's an OutsideContextProblem. Ultras don't exist in that universe, so the aliens have no ''need'' to be prepared for them, while stopping alien invasions is Seven's (and any ''other'' Ultra worth his salt's) day job. Of course Seven has the advantage.]]
* WhatDoYouMeanItsNotForKids: After learning the [[ScrewedByTheNetwork mist]][[MisaimedMarketing akes]] from ''Series/UltramanNexus'', ''Ultraseven X'' becomes more adult-oriented and [[DarkerAndEdgier darker]] for modern Heisei-era ''Ultraman'' viewers.