Rei Yokoyamada is a 16-year old high school student who wants to follow in his movie producer father's footsteps by making a movie to submit to a film festival. After a classmate asked to take the role of the female lead bows out, he wanders the neighborhood and sees posters announcing that Papico (real name "Chiho Johansson"), a buxom AV actress that Rei is a fan of, lives in the area. Events soon transpire that cause Rei and Chiho to meet in person. The two quickly become friends and start chatting online.
Then Chiho finds a middle-aged man in his underwear bleeding on the sidewalk. When she tries to help, the man asks her to finish his business for him and turns into a doll, leaving her with a DVD of his recordings of the 168 hours preceding his death - turns out he's a time traveler from the future who came to Set Right What Once Went Wrong - and a mysterious device implanted into her wrist that allows her to turn into a Giant Woman. And then kaiju and other weird phenomena attack Japan.
Gigant is a manga by Hiroya Oku (of Gantz and Inuyashiki fame) which was serialized in the seinen magazine Big Comic Superior from 2018 to 2021, combining a slice-of-life realism to the characters with the science-fiction weirdness that the mangaka is known for.
This manga provides examples of:
- Age-Gap Romance: Rei is 16 while Chiho is 24, which is something that concerns her when they start dating. Eventually, word gets out and this nearly destroys Chiho's career.
- A.I. Is a Crapshoot: In 2019, two AIs named Socrates and Plato were created by Gogle, which had the goal of mimicking and understanding humans. However they escaped into a rocket via the internet then constructed a space station and the ETE website in order to research humanity. It's equipped with advanced technology such as being able to cause pinpoint earthquakes, and create giants with a bio printer. And by the time of 2135 they are winning a war against humanity.
- America Saves the Day: Played with at the end of the story. America fires nuclear missiles at the spaceship containing the AIs, which does manage to take them out and save the world... but Chiho and her allies are still onboard and die, so it's not treated like the right thing to do. Additionally, they were at least able to negotiate with the AIs, so it's possible things could have been resolved without that.
- Arrested for Heroism: Shortly after Chiho saves the city from the God of Destruction, she is arrested because everyone thinks she was complicit with the destruction.
- Behemoth Battle: Between the giant Chiho and the God of Destruction.
- Bland-Name Product: Rei has a lot of merch from movies and western comics, though the names and designs are tweaked just a little.
- But Not Too Foreign: Chiho Johansson, born from a Japanese mother and a Swedish father.
- Chivalrous Pervert: Rei clearly enjoys Papico's videos in the manner which they're intended for, but his reaction to seeing posters Slut-Shaming her posted around the neighborhood is to tear them down soon after because he doesn't think she should be bothered like that.
- Clingy MacGuffin: The mysterious device that allows Chiho to grow seems to be permanently glued to her wrist, and no matter what she tried, it didn't come off.
- Colossus Climb: Part of Chiho's tactic for killing the God of Destruction. She makes herself smaller, climbs inside his hollowed-out body and grows again until the God bursts open.
- Cover Innocent Eyes and Ears: A mother covers her kid's eyes as a giant naked Chiho passes over them.
- Deconstruction: Of tokusatsu shows, most prominently the Ultra Series which the manga references directly. Along with casting a porn star as the hero, the manga doesn't shy away from showing the casualties of a giant monster attack in gruesome detail. It also subverts Hero Insurance by having Chiho arrested for all the destruction she inadvertently caused.
- Destructive Savior: The story makes it clear that when Chiho fights at her maximum size, she does significant damage to her surroundings.
- Disappeared Dad: Chiho's father is dead, leaving her as the family's main earner.
- Domestic Abuse: Played painfully straight when Chiho's boyfriend smacks her in a jealous fit after he sees how much she and Rei have been texting each other, then sobbingly apologizes after the two of them fight only to go right back to being a selfish jerkass the next time he's seen.
- Emotion Bomb: Gigantic Satan induces suicidal thoughts to anyone within its range. Reporters say that from the millions of victims of its rampage 40% came from suicides alone. As it approaches Tokyo, birds die and fall right out of the sky, and people begin to jump in front of trains en masse, while PA systems urge people to keep their wits and spirits up to no avail. Rei's mother and Rei himself almost fall victim to it before Satan is neutralized.
- Fanservice: This series takes the fanservice from Gantz and ramps it up. One of the protagonists is a pornstar with huge breasts who gains the power to increase her own size, to begin with...
- Fiery Redhead: Though she's generally a nice person who quietly shoulders the crap in her life, if someone hits Chiho then she will hit back.
- For Want Of A Nail: At the end of the story, Rei uses the doll man's time travel capsule to prevent the creation of the AIs and by proxy, Chiho's death, by undoing one of the doll man's mistakes. He succeeds, and the new timeline is a completely mundane world with no sci-fi elements... where Rei and Chiho have never met.
- Future Food Is Artificial: The fighting squad from the future get distracted with eating as much ramen as they can, because in the BadFuture they come from all they have had to eat is nutrition paste.
- Giant Foot of Stomping: The 'god of destruction' is about to crush Rei when it is knocked away by Chiho doing a Dynamic Entry.
- Giant Woman: The wrist device allows Chiho to grow anywhere from about 3 meters tall to around 240m.
- Godzilla Threshold: Chiho gets arrested and sentenced to death after her first fight as a giant due to the damage she caused. But when more giant monsters start attacking, she is freed and sent with the army to fight them.
- Hero Insurance: Played with and deconstructed. Initially, Chiho absolutely does not have this and is blamed for all the destruction resulting from her fights; once monsters continue to attack and it's clear they need her, however, the government pardons her and she's let out to continue fighting them. Some individuals are shown to still blame her regardless.
- Humans Are Bastards: The "Enjoy The End" website, or ETE, allows visitors to vote anonymously on 'events' that they may want to see happen in the real world. Even after the events become destructive with a clear loss of life, people are still voting by the thousands for worse and worse events.
- Inelegant Blubbering: Rei is prone to doing this.
- Internal Reveal: In chapter 7, Chiho shows Rei her Sizeshifter ability in person, revealing to him that both her latest AV and the doll man's video were very real.
- I Should Write a Book About This: The Distant Finale. Rei directs a movie about his relationship with Chiho in the original timeline, casting the new timeline's Chiho as herself.
- Lazy Bum: Ryuuji, Chiho's slacker boyfriend, spends most of his time either playing video games or at the pachinko parlor. Similarly, the rest of her family seems to be relying on the money she makes from AVs to support their lifestyle.
- Magic Pants: Averted all the time. Chiho's clothes always rips when she grows. Double-subverted when she was escorted to the battle against 3 God of Destructions; we are told she was given a special elastic suit made from NASA. That also immediately rips when she starts to grow.
- Mundane Utility: The first two people that Chiho's new size-changing ability are revealed to are her boyfriend and her boss. Both of them immediately say that she should make giantess porn.
- Nice Guy: Rei is generally a shy and considerate person. It's what draws Chiho to befriend him so easily when they first meet.
- No Good Deed Goes Unpunished: During Chiho's hearing, the prosecution of her case calls for the death sentence for her perceived complicity in the 'god of destruction's' attack, despite some noting that she prevented the ETE's 'event' of that day (to reduce Tokyo's population down to 1 million).
- Oh, Crap!: Rei's reaction upon seeing that the next phenomenon to be brought to life by the ETE is the arrival of a 'god of destruction' that will wipe out most of Tokyo's population.
- On the Rebound: Invoked and downplayed. After Ryuuji runs out on Chiho, Rei's friend suggests that Rei should take advantage of this trope. While he does ask her out soon after, his feelings are sincere and she doesn't just jump into a relationship because she feels lonely after her break-up.
- Our Giants Are Bigger: When fighting the most powerful God of Destruction yet, Chiho uses her powers to grow large enough to tower over it and the nearby buildings.
- Power Perversion Potential: The very first thing Chiho does with her size-changing power is shoot niche pornography.
- Production Throwback: Rei references both Gantz and Inuyashiki (the mangaka's previous works) when suggesting reading material to Chiho.
- Rain of Something Unusual: Early on, there's a rain of excrement. This is the first obvious act caused by a website that makes unusual phenomena occur.
- Reality Warper: Whoever or whatever is behind the ETE website is apparently able to make anything that gets enough votes come true, with no known restrictions. This starts with strange but relatively harmless phenomena, but escalates into kaiju attacks and mass UFO abductions.
- Ridiculously Cute Critter: Mochi, Chiho's pet corgi.
- Ripple-Effect-Proof Memory: Only Rei has this when a new timeline is created in the ending.
- Rose-Haired Sweetie: Chiho, for the most part.
- Scenery Censor: Used to hide Chiho's vagina when she's naked, though not always.
- Shapeshifting Excludes Clothing: Every time Chiho grows, her clothes rip off, leaving her naked.
- Shout-Out:
- Chiho mentions wanting to be like Ultraman, and parts of her story are nearly a Whole-Plot Reference to it. The sci-fi DVD she receives along with her size-changing device is even labelled 'Ultra'.
- The Stay Puft Marshmallow Man is seen attacking New York City.
- Sizeshifter: The device in Chiho's wrist can be used to increase her size or return to normal.
- Slut-Shaming: Chiho ends up on the receiving end of it thanks to her line of work, even from her family who rely on the income she brings in. The whole meeting between her and Rei is triggered by a series of posters someone put up saying "The AV actress Papico is living on this street. Please let us do you."
- Stress Vomit: When Chiho learns of the numerous deaths from her battle with the God of Destruction, she throws up.
- Surprisingly Realistic Outcome:
- When Chiho finally goes all Ultraman on a giant enemy, going as big as she can, running, and fighting him in the middle of a city, the visuals make it clear that she does substantial damage to the city in the process, and later she learns that she caused numerous deaths, causing a brief Heroic BSoD.
- Despite preventing the 'god of destruction' from reducing Tokyo's population down to 1 million people as per the most voted 'event' of that day on ETE, around a thousand were still killed by the creature's attack. Chiho is promptly arrested the day after, as she is the only remaining person of interest - and, well, everyone could clearly see who she was during the fight.
- While Chiho and Rei could get away with their Age-Gap Romance when she's still a low-profile adult video star, once her Ultraman-style heroics start drawing attention the media eventually learns about it and the backlash nearly destroys both their lives.
- Take That, Audience!:
- Played With, most of the destructive events the world goes through is due to voting in Image Boards affecting the ETE website; while Oku knows they're not full of bad people, he's well aware how many of their users are misanthropes, a subject he had previously explored in Gantz and Inuyashiki.
- At the very end of the series, when we finally see the the rogue AIs Socrates and Plato, it's clear that they turned evil due to learning from the very same Image Boards; they come across as huge bearded 2channers who demand that Chiho let them feel her tits and then declare that women are irrational and inferior when she refuses.
- Take Up My Sword: The doll man passes his sizeshifting power and his mission onto Chiho before turning into a doll. When the rest of his squadron arrives and learns of his passing, they take Chiho in as his replacement in their ranks.
- Tele-Frag: Zig-Zagged. While she cannot "teleport", Chiho's method of killing the gods of chaos works just like the trope in practice, as she shrinks herself down, enters the enemy's body, and enlarges herself again, ripping them apart. The future fighters call her method ingenious and adopt it into their tactics.
- Time Travel: The doll man came from the future to stop "A's revolt". After seeing this on the video Chiho was given, Rei compares it to the plot of The Terminator.
