The manga focuses on a young girl named Coco and her pet cat named Kuro, living together in a large mansion on the outskirts of town. The story details their day-to-day life and their interactions with friends from town. However darker things hide in the background, with monsters prowling in the forest, Coco's mysterious background and Kuro being no ordinary cat...
Kuro provides examples of:
- A Dog Named "Dog": Milk's cat is named Neko (which means cat).
- Aerith and Bob: We have Kuro, Coco, Sesame, Milk, and then we have Maria and Brenda.
- All of the Other Reindeer: The townsfolk tend to avoid Coco or act distant and cautious around her. They tend to talk about her behind her back, finding her creepy and are glad when she stops coming to town.
- Big Fancy House: Coco's mansion is huge and luxuriously furnished. It's traditionally been the town mayor's residence.
- Big Ol' Eyebrows: While they're not incredibly thick like other examples, Maria's and Doctor's eyebrows are noticeably bigger than the rest of the cast.
- Black Blood: What the monsters bleed.
- Blush Sticker: Combines this with a bit of Luminescent Blush. Basically everyone has them.
- Body Horror: Kuro can do some really weird stuff.For example, what happens to the monsters' victims. It's only been demonstrated on animals so far, but one can fill in the blanks for what happens to a human.
- Bratty Half-Pint: Sesame is a very...spirited young child, who foolishly messes with Kuro quite a bit.
- Brought Down to Normal: In the ending, Kuro seems to have gone back to being a normal cat. Maybe.
- Cats Hate Water: Kuro doesn't seem to mind water, as long as it's not in the water.
- Cerebus Syndrome: The story is starting to get more and more serious as the darker elements are slowly pulled into the forefront. After Milk tries to kill Kuro, Coco's mood shifts dramatically. She stops leaving her house and refuses to let visitors in.
- Cheerful Child: Coco, though she's starting to become less so as Cerebus Syndrome gradually kicks in and it gets harder for her to live in denial.
- Chekhov's Gun: The monsters become white and faded when they die. Their dead bodies are the source of the white flowers.
- Chest Burster: A weird example in the case of the monsters. The black worms are parasitic, but not to the monsters, because the worms are how they reproduce. That still doesn't stop the worms from exploding out of the monster's eye in a huge spurt of black blood.
- The Cobbler's Children Have No Shoes: The doctor discusses this. Coco grows the white flowers that're used to make the vaccine and the white paint that protects the town from the monsters. But since the vaccine can only be taken six months after a kid turns six years old, and Coco didn't get the vaccine at that age, she doesn't benefit from her own flowers.
- Combat Tentacles: Kuro has some which come out of its mouth. They're used for stabbing, slicing, and healing sick little girls.
- Creepy Good: We're briefly led to believe that that doctor may be up to something sinister when he picks up an animal corpse and is evasive with Maria when she asks about it, but he's only examining the effect the parasites have on beasts.
- Cynicism Catalyst: Maria became rather bitter after her brother got killed by the monsters when she was little.
- Daddy's Girl: A flashback shows that Coco adored her dad and wanted to be a respected florist like him.
- Dark and Troubled Past: Something happened to Coco's parents that led to them dying. Coco seems to have repressed the memory.
- David Versus Goliath: After what we've seen Kuro do to other monsters, the horror of seeing little Milk come after him with a knife lies not in how she might harm him. Also, the doctor and his pistol when he's attempting to defend her from Kuro's anger. They're both lucky Coco showed up.
- Don't Go Into the Woods: The forest surrounding the town is heavily monster infested. And apparently most of the world is too.
- Encounter Repellant: The monsters seem to dislike cold weather, with the big ones going into their lairs during winter, though possessed corpses seem more resistant. This is the only time of year when hunters can go into the forest and recover the belongings of their victims (for their loved ones) in relative safety. "Relative" meaning as much stealth as possible and heading back home if even one possessed corpse is spotted, as a conflict might attract more.
- Establishing Character Moment: The first thing we see Maria do is kick Kuro and call it a monster. Subverted later on when we see that she's not all bad.
- Everyone Calls Him "Barkeep": The doctor is just called Doctor.
- Extra Eyes: Animals infected by the monsters get really freaky spider-like eyes. Some of the monsters themselves have many eyes.
- Eyeless Face: Subverted with Kuro. Kuro usually doesn't have visible eyes but can make as many eyes as it wants appear anywhere on its body.
- Eye Scream: Kuro kills some monsters by impaling them through their eye.
- Gainax Ending:
- The readers' reaction to the ending was pretty much a universal "what?". What seems to happen is that Kuro kills every named character except Coco, but it turns out to be All Just a Dream. Kuro then sacrifices himself to turn Coco back to normal, and his body crumbles away as a result. But then somehow, in the middle of what's supposed to be the happy ending, where Coco is cured of her self-deception and is surrounded by all her friends, Kuro shows up once again as a normal cat. So, is the happy ending a hallucination and Kuro really did kill everyone? But that doesn't quite make sense either, since the only people in the mansion were Maria and Milk, yet we also see Kuro kill the doctor and Brenda. It's just one big Mind Screw.
- The epilogue clears things up a bit. It seems the monstrous part of Kuro merged with Coco so she could live a (relatively) normal life, even despite being unable to separate again.
- Friendless Background: Milk had one prior to meeting Coco. It's why she's so fixated on their friendship.
- Girlish Pigtails: Coco and Sesame.
- Gory Discretion Shot: When Maria's brother encounters a monster, we're only shown the outside of the building he's in while he screams.
- Hikikomori: Coco seems to be on the path to becoming one, having stopped going to town and drawing the curtains over the windows.
- Incredible Shrinking Man: In one of Coco's stories, Coco and Kuro smell a black flower that causes them to become the size of a bee.
- Innocently Insensitive: Sesame, a little girl, doesn't know it's a bad idea to draw Kuro as a multi-eyed monster and show the picture to Coco.
- Invisible to Normals: People who haven't gotten the vaccination can't see the black monsters, just the corpses they've possessed.
- Jerk with a Heart of Gold: Maria doesn't have a lot of nice things to say about Coco, but the two girls were once friends and Maria still cares for Coco. It's just that Kuro's presence and Maria's hatred for the monsters that makes their friendship difficult.
- Locked into Strangeness: Coco's hair changes to white, suggesting that Kuro has been gradually feeding off of her.
- Motherly Side Plait: Coco's mom.
- My Beloved Smother: Milk's mother is like this, at least as far as anything to do with the mansion goes. This is because of not only surviving of the previous mayor/flower gatherer's ill-fated attempt to expand the mansion grounds (if only because she showed up late for her job as a maid there), but she actually saw one of the victims being killed.
- Never Found the Body: The monster's victims don't tend to leave bodies behind, considering what usually happens. So the townsfolk create dolls in the likeliness of the dead person, which is instead put into a casket and buried.
- Nice Lady: Brenda, Sesame's mother and Coco's tutor. She's the only person who's consistently nice to Coco and doesn't seem to mind Kuro because it protects Coco.
- Nightmare Sequence: Coco has a nightmare where Kuro attacks her.
- Noodle Incident: Some "incident" happened at Coco's manor when her parents were still alive (or possibly even before they were born), which caused the townspeople to become deeply mistrustful of the manor. It's eventually revealed that the town mayor had ordered the land adjacent to the manor to be taken back from the monsters. Those woods were cut down and the land was treated to keep the monsters away, but when a celebration was held on that land, the monsters found a way to massacre a bunch of villagers, including the mayor. That land was sealed off, but for many people, the manor is still a grim reminder that they aren't as safe as they like to think.
- Posthumous Character: Coco's parents, shown only in flashbacks. Their deaths have a large impact on Coco and the story.
- Puppeteer Parasite:
- When monsters die as a natural part of their life cycle, they expel a bunch of black worm-like creatures from their dead bodies. This worm infects a host, gaining control of the host's body and feeding off of it for nutrients. Eventually, the host will become "Possessed" (i.e, the host ends up becoming another monster). So far we've only been shown what happens when a worm infects a dead animal. The townspeople assumed that Kuro was a Possessed, however Doctor theorizes that Kuro is the result of a worm infecting a gravely injured but still living animal, resulting in a sort of previously-unseen symbiotic relationship, wherein the host body undergoes dramatic physical changes while also retaining its memories.
- It's revealed that this is the fate of Coco's parents after they suffered a car accident.
- Red Eyes, Take Warning: The monsters have prominent red eyes, and Kuro can get red eyes if especially threatened.
- Secret-Keeper: At one point Brenda gets the opportunity to talk to Kuro alone, and acknowledges that he's been protecting Coco. She doesn't tell Coco about Kuro's odd traits because of the girl's deep denial.
- Shrinking Violet: Milk.
- Story Within a Story: A few chapters features stories that Coco wrote, which is about her and Kuro going on imaginary adventures.
- The Symbiote: According to Doctor's theory, one of the black worms formed a symbiotic relationship with the original Kuro, when the cat was seriously injured but not dead.
- Tragic Keepsake: There's a group of townspeople whose job is to provide these. They venture out into the forest during winter, when the monsters are inactive, to find objects to bring back to town and give to the deceased's loved ones.
- Trauma-Induced Amnesia: The doctor thinks that the reason why Coco is so upbeat is because the she's forgotten the "accident". Coco herself never shows any inclination to wonder where her parents are, and Brenda discovers a large build up of dust in and around her parent's room compared to the rest of Coco's immaculate house, which implies Coco has been subconsciously avoiding anything about her parents. Ultimately, Coco appears to be aware of what happened but is in deep, deep denial.
- Troubling Unchildlike Behavior: Milk freaks out when she sees Coco talking to Maria, and later tries to murder Kuro so that she can have Coco's friendship to herself.
- Undying Loyalty: Kuro loves Coco and refuses to leave her side.
- Weirdness Censor: Coco doesn't seem to notice that Kuro is not a normal cat and apparently can't see the monsters. Justified in that Coco didn't receive the vaccination that'd allow her to see the monsters and because she actively denies anything is strange about Kuro.
- Yandere: Downplayed with Milk. She sees Kuro as an obstacle preventing her from achieving a closer friendship with Coco and tries to kill it. Coco doesn't take that very well.
