Musashi Haruno, a member of the science investigation team EYES with dreams of peace between humans and monsters, has to deal with the Chaos Header virus, which is corrupting Earth's monster population into violent berserkers. Soon enough, he meets again with his childhood friend Ultraman Cosmos, and together they strive to heal the monsters' blight.
Cosmos takes a much Lighter and Softer approach to the formula, with a kinder and gentler Ultraman that mostly fights on defense and prefers to save monsters instead of killing them. While the series is a major opinion-splitter among Ultra fans, the movies are generally well-liked.
Ultraman Cosmos provides examples of the following tropes:
- Alternate Universe: From the Showa-verse, Tiga/Dyna-verse, and Gaia-verse.
- Anti-Villain: Many in this series, the best example being Basical from First Contact.
- Big Bad: Chaos Header.
- Gondor Calls for Aid: The bonus of living in a universe where many Kaiju and aliens are decent beings is that they will come to Cosmos's or humanity's rescue if needed.
- Eldritch Abomination: Chaos Header. Though it turns into Lovecraft Lite territory once its origins are discovered and Musashi discovers that there's a way to communicate with it and that it is capable of feeling emotions.
- Even the Loving Hero Has Hated Ones: Though Cosmos and Musashi are both pacifists who don't really harbor hatred, even towards most of their enemies. Not so much with the Alien Nowars, whose enslavement and transformation of Kaiju into cyborgs against their will makes any sympathy either could have towards them go away. In fact, Nowar's last appearance in Episode 53 has Cosmos kill the last invading force without hesitation once their actions cause the death of the Baby Arados he was trying to protect from them. Later on, in Ultraman Saga, Alien Bat proves despicable and cruel enough that Cosmos and Musashi forego any diplomacy and doubtlessly help the other Ultras kill Alien Bat once and for all.
- HeelFace Turn:
- Many of the monsters do this, due to Cosmos preferring to pacify or purify them instead of killing them. Likewise, a good bunch of invading aliens also turn over a new leaf, either in the past or during the show
- Chaos Header ultimately does so in the end, transforming into an angelic being and leaving the planet willingly upon being purified and having a Heel Realization. We find out in a follow up that it becomes the guardian of a planet acting as the sanctuary for benevolent or benign monsters.
- Lighter and Softer: One of the lightest entries in the franchise.
- Lovecraft Lite: Chaos Header.
- Multiform Balance: Interestingly, at first this is less 'this form is strong and this one isn't' and more 'combat mode and pacify mode.' Luna form has no Finishing Move and largely is devoted to pacifying and purifying it's opponents while Corona mode is more combat based and actually capable of using lethal force. Eclipse Mode is a combination of both and has the ability to do either, and it's Finishing Move can purify good monsters and destroy evil ones (sometimes at the same time).
- Rousseau Was Right: Many of the Kaiju and aliens, if not the humans, are decent beings in essence. This includes Chaos Header.
- Space Whale: The Fake Space Whale Jirak, who is gentle as can be. Then Chaos Header does what it usually does.
- Technical Pacifist: Cosmos, to the point where his default Luna Mode has no finishing attacks at all. He will only switch to his more powerful Corona Mode when there is absolutely no other option or when he's facing something that's completely evil.
- The Virus: Chaos Header infecting living (and non-living) beings with its essence to turn them aggressive and irrational.
- Turns Red: Cosmos changes color from blue and silver to red and silver with blue patches when transforming into his Corona Mode. This is justified further by the fact that Cosmos usually changes into Corona Mode once he has suffered at least some injury.