Yukkuri House Yu
Cockroach Yu
Based on
Depends from the main species
Depends from the main species
Depends from the main species
Special Abilities
Depends from the main species
Depends from the main species


House Yus on a persons finger-tip. While generally not usually this size, small size is to be expected.

A subspecies of yukkuri.


They're a variations of the main yukkuri species, evolved as pests of human houses. As such, they're generally smaller (thus less resilient) than wild yukkuris of the same species, never outgrowing the usual koyukkuri size.

Possibly related to the "Mini-Yukkuri" often marketed as pet yukkuri in several stories, the house yukkuri, as cockroaches, tend to live secretive, hidden lives, sneaking out their nests between furniture items and in cracks in the wall to hunt hunt (in their case, steal) some food. They seem much less picky than their wild and trained counteparts, eating mostly everything that's even barely edible, and even ticks and carpet bugs.

House Yu characteristic and behavior are a cross between Wild Yukkuris and Stray ones: their little body mass allows for a stealthier life and a reducted need for food, so they're able to hide in human residences for a huge amount of time (much like cockroaches in human housings, thus earning the nickname of "Cockroach Yus"), breeding in vast numbers.

House Yu in fact are the one of the few shown to retain the egg parturition shown in early Yukkuri stories, possibly because their lack of mass and need for constant movement doesn't allow for stalk or mammalian forms of reproduction, so they leave behind a large amount of sugary eggs, hatching in no time.

House Yu may create, along with their "Easy Place" (their den), several storages for stolen food, usually in dirty, unkempt and hard to reach places, as the cables behind a computer or under a cabinet.

Despite their clumsiness and naivete, House Yus are so adept at hiding and doing hunt hunt to be almost undetectable by humans: in "House Yus", a story, a Reimu house yu due gleefully confessed to have "given Yukkuri's first kiss kiss to Mister Human", the owner of the home, waking up at night to suck moisture directly by his sweaty skin while asleep.

However, their naivete works against them, even hampering their ability to hide, leaving several flaws to exploit to get rid of them. For example, koyukkuris are usually even smaller and slower than their normal-sized counterparts, thus more likely to be left behind during a ride. Then, their natural tendency to hoard sweets sweets make easy for an house owner, upon discovering an Home Yu nest that he's unable to reach, leaving a plate with a small pile of sugar: the entire House Yu pack will hop merrily out of their hole, munching on the sugar and loudly declaring their "happiness" for the unexpected find.

Due to their size, even a potato chip is a large amount of food, adequate for an average House Yu family, thus they don't share the constant denutrition of the Stray Yukkuris. Furthermore, their lifestyle is more energetic than than the average lazying around, begging or roaming slowly and pitifully of their "gutters" brethen, thus an House Yu looks healthier and more chipper, even if still dirty and unkempt by having to squeeze itself in dusty, small places.

Relationship with humansEdit

House Yus are generally seen as pests in human homes that can spread germs and can generally make a mess of things. House Yus, despite lacking the concept of property as the rest of their race, seems to have an instinctual knowledge of "Mister Humans" as "Individual who'll make Yukkuris uneasy if they find them", thus they avoid to contact them as much as possible. Upon contact, interactions between a human and an House Yu will follow the same pattern of average ones.

Marisa Kirisame has been shown as having a Yukkurarium filled with House Yus: their meek disposition and their tastebuds educated by eating human trash make them excellent for disposing of organic waste. Any trash given to an hungry clan of House Yu will become expired bean paste and then compost.

Other homeowner may instead want to exterminate House Yukkuris, because of their lack of hygiene and high breeding rate: the best course of action is aquiring a badged pet yukkuri (preferably a predator-type like a Yukkuri Remilia or a Yukkuri Flandre) and ask it to keep tabs on the House Yu population.

Yukkuri Pet Shops also sell "Yu Motels", cardboard boxes with a sticky floor, combining the main structure of a cockroach motel (a small box with a sticky floor and insect bait) with the genetic need of Yukkuris to occupy an "Easy Home" and searching it for tasty food, and special sprays, capsicine based, that while harmless for humans are highly effective on Yukkuris.

Another surefire way to deal with a massive House Yu infestation is spraying the poisonous gas "Yurusan". As with cockroach extermination, the Yurusan may be poisonous also for humans, pets and pet yukkuris, so the human using the Yurusan is encourage to leave the house for at least two hours after spraying. The Yurusan is highly effective, and will seep in every nook and cranny of the house, killing off the Yukkuri pests or severely weaking them, making them easy for being taken away and/or killed.

For those not wishing to harm House Yus, but still want them gone, a simple trick can be used by tricking them to enter a cage that is filled with sugar or other foods. Once captured, the yukkuri can then be simply removed from the home. Another method is to vacuum up the House Yus and release them, though this poses the risk of killing the smaller koyukkuri and eggs.

Some humans have reported training house yus to act as their personal "house cleaners", removing dirt and grim along with insects in exchange for food and shelter. In these cases, the owner of the house captures a family of house yus and gives them the ultimatum of working for the owner or being exterminated. Aside from this, the cases start to differ with success being reported along with failure.

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