Anime / Oneirosea

Oneirosea is a Cyberpunk Shonen anime that blends Work Com and Fighting Series elements.

Hiro Nimura is a teenager who, after two years of organizing files as an intern, has just achieved his life's dream: to join Alcyon Corporation as a proper Demon Slayer. His first order of business is to find the woman who saved his life from a demon 11 years ago and thank her properly... but she's not in the employee records, and nobody he talks to has any idea who she is. Between demon-slaying missions with his newly assigned team, he looks into his mysterious saviour, and eventually uncovers a vast conspiracy that the seeming-benevolent company is hiding from the public.

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This anime provides examples of:

20 Minutes into the Future: Oneirosea is set in a vaguely near-future Cyberpunk Alternate Universe, in which there's a lot of shiny new technology but the culture seems pretty similar to real-life Japan.
Advert-Overloaded Future: Semikawa's buildings are covered in multiple-storey hologram advertisements for events, products, virtual idols, and so forth.
Android Identifier: Diel shells have bar codes on their faces to identify them as nonhuman.
Artificial Limbs: Cybernetic replacement limbs are widely available technology. Labyrinth specializes in designing and manufacturing them; the faction we see in the story focused on oneiric research is an offshoot.
Astral Projection: Used by Labyrinth agents to observe and study oneirosea, since Alcyon won't share the technology that lets you visit in person.
Aura Vision: Those with powers can learn mist-sense, and since souls in this world are made of mist, they can use this to locate and track others. Sensing non-living things with mist-sense is much harder, and since Hiro isn't very good at it, we get a few eerie scenes of him activating it and seeing ghostly outlines of people hovering in the air where they would be inside their apartments.
Battle Aura: Mist-users can see auras, and people with more power have larger and more solid ones. Their colors seem to correlate with personalities, too.
Beat the Curse Out of Him: In order to exorcise changelings, their physical body has to be rendered unconscious. Alcyon Corporation prefers to do this by peacefully immobilizing them and then using hypnotic drugs in order to minimize long-term damage... but since the changelings have access to their demon powers and are often fighting back, they sometimes resort to this trope.
Big Damn Heroes: The Benthic Strike Squad arrives at the Inverted Castle just as Hiro has been overwhelmed and nearly killed by a demon, and they handily sweep the place. Deconstructed later on, when Ichika points out how strange it is that Alcyon Corporation sent a bunch of twilight-rank divers to deal with the demons when the Benthic squad could have handled them in minutes. She digs into it, and it turns out the company intentionally allowed the situation to escalate in order to profit off the resulting chaos.
Bizarrchitecture: As its name implies, the Inverted Castle is an upside-down castle clinging to the ceiling of a cave, with its towers spiralling downwards.
Body-Count Competition: Akagi's favorite game. He tries to goad the rest of the Benthic squad into playing it with him, with mixed results.
Bread and Circuses: After their reputation takes a hit in the Labyrinth Arc, Alcyon Corporation stages a huge festival and tournament to pacify the public.
Broken Pedestal: Seems to be a recurring theme throughout the series.

Hiro idolizes Alcyon Corporation as a whole, since one of its agents saved him when he was a child. As his efforts to find his saviour lead him to dig deeper and deeper into the company's secrets, he finds it increasingly difficult to hold onto his idealized image of them.
Ichika fanatically idolized her supervisor Misaki, right up until she found out Misaki knew about many of the company's unethical experiments all along and cooperates with them because she believes they're for the greater good.

Corporate Conspiracy: Labyrinth's Japan branch claims to be research-focused, but is actually hatching a plan to develop their own version of the moon pool so they can destroy oneirosea entirely.
Creature-Hunter Organization: Alcyon Corporation's offense and defense divisions exist to exterminate demons who have become a threat to humanity.
Custom-Built Host: Diel shells are android bodies designed to host demons, so they can cross over into reality without possessing and killing a human.
Cyberpunk with a Chance of Rain: The weather in Semikawa seems to be wet and miserable year-round. Hiro, who's lived there all his life, expresses surprise when it starts snowing instead of raining around Christmas. Aobashi is better, but it's implied it's only sunny there because of weather-control technology.
Dead All Along: The woman Hiro is searching for, Yui Amagai, was killed when she tried to turn against Alcyon Corporation 10-11 years ago, shortly after saving his life. He doesn't find this out until after spending a good amount of time with a demon with her face.
Death of Personality: If a changeling manages to completely bond with the body it's possessing, the original human soul is gone forever and can't be saved.
Demonic Possession: Demons can infiltrate human bodies through their dreams, and if they manage to go long enough without being exorcised, bond with the body permanently while the original human soul is left to dissolve in oneirosea.
Demon of Human Origin: One of the harmful cult beliefs that Alcyon Corporation tries to debunk is the belief that people who die in oneirosea will become demons, granting them a form of eternal life. In practice, the vast majority of souls in oneirosea will simply dissolve when their body dies. It's not completely impossible, though - Yui's soul became a powerful disguiser demon that retains most of her human appearance. Though it may be more accurate to describe the demon as a new being with some of her memories, rather than the same person...
Did I Mention It's Christmas?: Hiro's semi-finals match during the Goodwill Festival takes place on Christmas Eve (or at least it was supposed to - he ends up brawling with Ichika instead), but aside from snow and some Christmassy decorations around the arena, it's not really mentioned.
Destructive Saviour: The offense division has this reputation to their rivals in defense, since they can blow up the oneirosea without having to worry about property damage fees coming out of their paychecks. When Ichika gets shuffled into defense, her new coworkers assume she'll be the same, and are surprised to see her precise control over her mare.
Dream Land: Oneirosea. It's an alternate dimension made of mist, a form of energy generated by human dreams, and people's souls physically go there when they dream.
Dream Walker: Anyone in oneirosea can physically walk into dreams currently taking place there, and interrupt or influence things.
Eating the Enemy: Demons who want to become stronger often resort to this, since demons can absorb the mist energy of other demons they consume and integrate it into themselves. This sometimes gives them their victim's powers, knowledge, or even personality traits. Clover was fond of this tactic back when they were in oneirosea, and in an early mission leaps out of their shell in order to devour a fallen foe before being informed that they're not allowed to do that anymore.
Eldritch Location: Being a Dream Land, oneirosea doesn't follow reality's laws of physics at times. It's possible to walk in a circle and somehow end up in a different zone than before. Thus, divers need to learn mist-sense before they can properly navigate.
Eldritch Ocean Abyss: While not literally the ocean, oneirosea's deeper zones are clearly designed to invoke this feeling, complete with a weather phenomenon similar to marine snow and terrifying fish-like demons.
Enchanted Forest: The shallower zones of oneirosea are fog-shrouded forests, and they're mysterious places where anything can happen because they're literally made of magic.
Eye-Dentity Giveaway: Incomplete-phase changelings are depicted with the concentric circle eyes of the demon doing the possessing. This seems to be Stylized for the Viewer, though, since characters in-universe without mist-sensing abilities are unable to distinguish them from the possessed human.
Eye Motifs: Demons have distinctive eyes with concentric circle patterns instead of separate iris / sclera / pupil, which symbolize their sense of identity. There's a decent amount of focus on Hiro's artificial eye as well, and later these two uses overlap when he figures out he can use it as a vent slot.
Fantastic Drug: "Glass" is a drug that affects demons and diels similarly to how alcohol affects humans. Alcyon Corporation's R&D division initially developed it for combat purposes, but when it proved too impractical for that, they started serving it at company bars instead.
Fighting the Lancer: Hiro and Ichika butt heads on multiple occasions, but it's played much more seriously at the end of the Goodwill Festival Arc, where Ichika drags Hiro into a raw close-combat duel in order to break him out of his denial and back to reality.
Good Thing You Can Heal: Since diels have robot bodies, their limbs can be replaced with no long-term consequences except to the diel's paycheck. As such, their arms and legs get spectacularly exploded with curious regularity so the author can demonstrate this fact to the audience. It doesn't help that the main diel character (Clover) is a weirdo who will sometimes choose not to dodge non-fatal attacks out of curiosity for how they feel...
Goroawase Number: The author seems to be fond of these, especially when it comes to character birthdays:

Hiro's birthday is March 9th; 3/9 can be read as "san-kyuu", or "thank you", reflecting his cheerful and grateful attitude. He also wears a jacket with the number 16 printed on the back (16 can be read as hi-ro, his name).
Ichika's birthday is 8/9, "hana", as a reference to her Flower Motifs.
Clover's birthday, 4/28, can be read as "yotsuba" / four-leaf clover.

Hologram: Much of the futuristic tech in the setting is hologram-based. It shows up everywhere, as wearable accessories, integrated into phones, replacing billboards, and so forth. Unusually, Hard Light is explicitly stated to be impossible.
Hunter of His Own Kind: Diels in the offense and defense divisions are tasked with defeating more malevolent demons. Few diels have qualms with this, since demons routinely eat each other for a power boost anyway.
Inhumanable Alien Rights: Diels are said to be in a sticky in-between legal position. They have some limited personhood and rights, being able to take part-time jobs, get married, or get driving licenses, but their robot bodies are Alcyon Corporation property, so for most intents and purposes Alcyon has full control over them.
In Spite of a Nail: Oneirosea takes place in an alternate universe where human dreams create an alternate dimension full of demons that can possess them. However, most world history and culture seems to have shaken out exactly the same as in real life, aside from a few offhand gags about historical shamans using oneirosea to communicate or Christianity depicting hell as watery instead of fiery.
Intelligent Forest: The Pale Forest shows shades of this, its layout shifting and changing to prevent the team from leaving. It turns out the forest isn't a lair; it's the mycelial body of a single enormous demon, which has spread itself across a great distance in order to lure in more prey.
Involuntary Group Split: The Inverted Castle infiltration goes wrong when a guardian demon notices and attacks the party, scattering them and forcing them into a series of 1v1 duels instead of travelling as a group as they'd planned.
Knight of Cerebus: There are hints that Alcyon Corporation isn't the most ethical company and Hiro's idealization of them isn't healthy from the very beginning, but in the first few arcs it's mostly played for laughs, and the focus is on the Monster of the Week or the Arc Villain instead. When Laplace nearly kills Hiro and he manifests a second, impossible power in self-defense, it shows there's something very important that the party hasn't been told, and the focus begins to shift.
Layered World: Oneirosea is layered over reality like this trope, with each location in oneirosea corresponding to a location in the real world. This means that dealing with some demons is much more urgent than others - it doesn't really matter if a demon sets up shop in the middle of the Pacific Ocean, but if it starts hunting in the equivalent of a high-density residental area, things will break bad very quickly. Due to Alien Geometries, Oneirosea is somehow also smaller than reality, so it can be used as an Extra-Dimensional Shortcut.
Magical Gesture: Mist-casting, a system of wizard spells, requires precise gestures to cast. More powerful spells require two or even three hands to form the gestures, necessitating multiple casters to work together.
Magic Enhancement: Mist-boosting is the art of using mist energy to enhance your strength and durability. It's one of the basic mist-manipulation powers.
MegaCorp: Alcyon Corporation, of course. They're described as a pharmaceutical corporation primarily, but the story focuses on their oneiric research and demon-slaying divisions, and they apparently have a number of other side projects including GMO crops and a virtual idol. Their rival corporation Labyrinth (primarily a cybernetics manufacturer but also muscling into the oneiric research space) counts as well.
Mental World: Every human has one of these, and it's where their dreams take place. Literally: when they dream, their soul floats into oneirosea and their mental world expands into a large bubble containing their soul where the events of the dream play out. Domains are said to be techniques that externalize mental worlds into the real world, though this isn't confirmed.
My Defense Need Not Protect Me Forever: During the invasion arc, our protagonists learn this is what makes changelings so dangerous: all they have to do is survive until they run out the timer and bond with the body they've stolen, and they become impossible to exorcise.
Neon City: Semikawa is a futuristic cyberpunk city covered in colorful glowing signs and advertisements.
Non-Uniform Uniform: In theory, Alcyon Corporation's uniform consists of a dress shirt, tie, slacks, and division-colored armband. In practice, they're so lax about uniform regulations that practically every named character wears something different. We've seen jackets, jewelry, shorts, skirts... basically the only piece that's actually consistent is the armband.
One Person, One Power: Each mare or wake is unique to its wielder; even though some types are more common than others (e.g. several characters have ice manipulation powers), the specifics of how they work and what they're suited for are usually different. Downplayed though, in that there are some additional powers that can be learned by anyone, like mist-casting.
Our Demons Are Different: Demons are Dream People that spontaneously form from the mist in oneirosea. They vary greatly in physical form and even sapience, with some being humanlike and others being barely sentient. They seem to be called demons primarily because of their ability to possess humans and take their bodies for themselves; in fact, this is the only way they can cross over to the real world.
Our Souls Are Different: A "soul" refers to the mist stored within a human's body. It contains their dreams and memories (and possibly personality), but in a form that's difficult to read or access. If your soul is damaged, you experience brain damage symptoms of varying intensity; lucky people can regenerate more mist to replace the damaged parts, though, and eventually go back to living normal lives. These are the hard facts, but there are also many false beliefs about souls (e.g. that they automatically go to oneirosea when you die) that Alcyon Corporation struggles to quash.
Partial Transformation: Diels have "vent slots" built into their robot shells that allow them to selectively reveal parts of their demon true form, in order to gain access to their demon powers without fully exposing themselves to reality and burning away. As a lucid changeling, Hiro eventually gains the ability to do this as well, though he's limited to doing it through injuries and his artificial eye.
Personality Powers: Unique powers are based on the user's dreams (for humans) or sense of identity (for demons), so this trope is in effect by default, though for some people it's more obvious than others. For example, Ichika has a detached and cold personality, Clover is curious and loves taking things apart to see how they work, etc.
Phlebotinum Pills: Demon cells, which grant powers when ingested by compatible people.
Playing with Syringes: A secret branch of Alcyon Corporation's R&D division is researching ways to tell normal humans and complete-phase changelings apart, and keeps a number of changelings in captivity to prod and cut apart for this purpose. So far, the consensus seems to be that there is no difference... which is terrifying for a variety of reasons.
Portal Pool: Moon pools, the portals used to travel between reality and oneirosea, look like shimmering pools of water when they're activated.
Power Limiter: The Benthic Strike Squad have power limiters screwed into their skulls, because they have so much destructive power that they can't be allowed to use them unchecked. When deactivated, the mist flowing out of them look like energy horns.
Random Power Ranking: Both Alcyon Corporation agents and demons are classified using ocean zone terminology - sunlight, twilight, etc. A sunlight-rank demon is a demon whose power level is typical of those found in the sunlight zone, and so forth.
Research, Inc.: Both Alcyon Corporation and Labyrinth could be seen as this, since their R&D departments are studying oneirosea and developing technology based on its properties.
Ridiculously Human Robots: Diels are virtually indistinguishable from humans, have human-like levels of strength and limb rotation ranges, and can eat food, among other things. Justified since lots of demons are curious about various aspects of human life, so the functions were built into the shells to make them more appealing.
Roofhopping: Some Alcyon Corporation agents take to using this as a way to commute so they can avoid the awful traffic that's universal in the city.
Sitting on the Roof: The Alcyon Corporations HQ roof is a popular hang-out spot for offense agents, even though it's technically against the rules to loiter there.
Superpower Russian Roulette: Humans who accumulate too much mist in their souls can spontaneously develop superpowers... but because this process is unpredictable and uncontrolled, they often come with unpleasant side effects, to the point where these powers (natural mares) are often considered chronic illnesses rather than anything positive. Some people lack Required Secondary Powers so they can't use their powers properly, while others can't control them or turn them off. Alcyon Corporation's medical division provides support and medication to people afflicted with these.
Super Toughness: Mist-boosting allows you to resist ridiculous amounts of damage. Characters are often thrown through buildings or trees and stand back up with barely a scratch.
Transformation of the Possessed: Powerful demons can mutate the bodies they possess, and these changes stick around even if they're exorcised. Misaki for example was possessed by an abyssal-rank demon as a teen, and half her face has been twisted into a permanent toothy grin surrounded by flaps of fin-like flesh.
Terminal Transformation: When extremely powerful demons possess a human body, they inevitably mutate it so severely that the body can no longer sustain life, which kills both the possessed and the demon. Some demons who want to possess humans actively avoid getting stronger, so they won't get this effect.
Tournament Arc: Half of the Goodwill Festival Arc centers around a tournament Alcyon Corporation is holding in order to repair their reputation, which Hiro enters. Since it's all being aired live on TV as entertainment, the matchups are explicitly being seeded to generate the maximum amount of excitement, justifying the smooth progression often seen in these kinds of arcs. In a twist on the standard formula, Hiro reaches the finals... and then loses his final match by way of disqualification because he's too busy getting his ass beat by Ichika to show up in time.
Unskilled, but Strong: Labyrinth-aligned characters tend to be this, since the company hires a lot of people with natural mares and focuses on suppressing their side effects over teaching control techniques. As such, Labyrinth agents pack a ton of firepower, but usually use it in straightforward and uncreative ways.
Virtual Training Simulation: Alcyon Corporation has them. They're referred to as training sims, but they're actually created by specialists who generate training landscapes inside their lucid dreams, then allow agents to enter them.
Vitriolic Best Buds: Himeno and Samejima. Ichika comments that they seem like the type to enjoy arguing, which is probably why they're still working together after all this time.
Weaker in the Real World: Since they're made of dream energy, demons cannot visit reality unless protected by a physical body; otherwise the harsh matter of the real world will burn them to death. Most of the ones who aspire to "become real" do so by taking over human bodies.
When It All Began: The changeling invasion 11 years ago. Hiro was possessed and nearly died, sparking his desire to join Alcyon Corporation so he can find and thank his saviour. It's often seen in the form of dreams and flashbacks.
Working for a Body Upgrade: Diels can use their paychecks to pay for upgrades to their shells, both cosmetic and functional.
World of Technicolor Hair: And eyes. Bio-modification technology is available that lets people easily change their hair and eyes to a variety of candy colors, and a lot of characters have done so.