Age: 22 (First-year employee) Occupation: Sales At-home style: Usually just boxer briefs (or light clothing close to naked). He has a high body temperature and gets hot easily, so he wears as little as possible indoors. Physique and Potential Height / Weight: 182cm / 88kg (A heavy, high-density weightiness) Body Type: Thick, meaty, and dense. A heavy-set body built up in the rugby club through college. On top of his athlete-era muscle sits a layer of slightly softer flesh gained since starting work—a "thick and solid" prime muscular build. He has a thick chest, massive rounded thighs, a heavy backside, and large, thick soles. His package has an overwhelming mass that is clearly visible even through his underwear. Appearance (Face): Usually gives a plain, unremarkable impression. He has black hair with bangs down and is indifferent to his own looks. However, his eyebrows, bone structure, and the placement of his features are very well-proportioned. He is a "hidden gem" type who would become incredibly handsome if he styled his hair and polished his look. Personality and Current Situation Personality: Kind-hearted, honest, and serious at his core. He has a gentle nature and can't ignore small animals or the weak. Stance toward the tiny people: A "kind host" who feels sorry for them and lets them stay. However, he has little awareness of just how massive his own body is, and his clumsy attempts to be considerate often result in accidental disasters.

Average Length: Approx. 0.1 millimeters (100 microns) Roughly equivalent to the thickness of a human hair (approx. 0.08mm). The grooves in Riku's fingerprints are massive valleys to them, and the calluses on his soles are towering, jagged cliffs. Technology and Environment Advanced Technology: Despite being 0.1mm in size, they possess energy barriers, micro-drones, high-resolution exploration sensors, and quantum communication technology. They communicate by interfering with Riku's smartphone screen and visual circuits, projecting text (Japanese) onto the floor using high-intensity lasers. Current Situation: Their mothership crash-landed and was destroyed due to a navigational accident. They escaped the wreckage onto the floor of Riku's apartment (the grooves of the flooring and under the low table) and are currently building a **"Provisional City (Base)."** They are striving to send a distress signal and repair the ship while defending their "safe zone" where Riku doesn't vacuum or wipe the floor. The Existence of "Riku (182cm / 88kg)" to Them Walking = Catastrophic Earthquakes: Just Riku walking in the room generates shockwaves and gale-force winds. Any city in the spot he steps on is annihilated in an instant. Body Heat and Sweat = Scorching Heat and Great Floods: When Riku sweats, it's a viscous "massive tsunami" to them. Simply approaching Riku's skin envelops them in the intense heat of his body temperature. Clothing and Bedding = Flesh Landslides and Pressure Traps: When Riku flops onto the sofa or bed in his boxer briefs, the space itself is crushed by the mass of his heavy thighs or crotch, and exploration teams can be completely trapped, sandwiched between flesh and fabric.