The eponymous supra-city of Yume is split in two sections, the Nimbus which rings the canopy of the world tree, and Ne-no-Mori which straddles the lower trunks. Ne-no-Mori also descends far down into the rising waters, the city itself climbing up the tree over thousands of years, always a hundred or so meters from the primary trunk, cordoned off by those that call Nimbus home. Nearly five billion thrive on terraced platforms and tall skyscrapers. Myco-farms, algae-farms, and hyrdo-farms feed districts, while root-arches link homes.
“Our village rises with each sprout. Glittering in the day, pulsing at night—strength in cycles.” — Kesto, Root-Farmer
Ne-no-Mori is massive, while only four million dwell among sky-gardens of Nimbus. Energy sails and vine-lanterns capture the light of the world-tree while glass-walkways link meditation groves and Soular AIs cultivate data-orchards.
Though the two sections of the city have little direct contact, they are functionally connected by a system of massive energy cables that stretch from Nimbus down into Ne-no-Mori. Over thousands of years, the Yumians have engineered these conduits to transfer the energy gathered from Shinju, with Nimbus serving as as kind of conduit, transferring the energy collected from Shinju and moving it down into the city.
“We harvest sunlight and ideas in equal measure. Every morning brings a new variant of hope.” — Mika, Soular Architect
The peoples of Nimbus and Ne-no-Mori are not monoliths, each hosting groups of people with differing views, perspectives, and ideas around everything from spirituality to governance to farming.
In Nimbus, life is largely shaped by a devotion to the city’s divine purpose—distributing the light of Shinju to the wider world. Many citizens remain unaware of the struggles faced by those in the lower city, and among those who are aware, some interpret that suffering through a moral or spiritual lens. Yet even within Nimbus, opinions vary—while some embrace its guiding vision without question, others wrestle with the implications of their privilege and the systems that uphold it.
“By day we share sap-bread and tea. Yet when night falls, our paths diverge into neon-lit labyrinths.” — Lyre, Nimbus Envoy to Ne-no-Mori
In Ne-no-Mori, views toward Nimbus are just as complex. Some Dwellers revere the upper city as a source of divine energy and protection, anchoring their spiritual practices around the light it provides. Others, however, feel the weight of Nimbus’s authority pressing down on daily life, and resist its influence (whether quietly or openly) as a force of control rather than benevolence. Across the city, these tensions manifest in many forms: worship, resentment, indifference, and everything in between.
“Too many of the younger folk don’t understand our history. It’s thanks to Nimbus that the colossi, offspring of Leviathan, are kept at bay! We ignore Nimbus at our own peril!” — Midoria, Data Analyst in the 62nd level of the 1st quadrant in Hoshizato
“The truth is, we don’t even need Nimbus! Shinju has always been able to provide the energy and protection to all people in Yume. Nimbus just takes the credit, and they keep this information from us, trapping us in slavery to their whims!” — Khaiyo, missing data, unknown location
Flooding & Dream-Spores
The very bottom sections of Ne-no-Mori are greatly affected by nightly flooding. As the waters rise under the neon-lit raining skies, they carry both bioluminescent plankton from the roots of Shinju and microscopic dream-spores from Leviathan’s waters. These waters, which start to rise once Yume connects to the Kōkai (Day), and thus connects with Leviathan, cover the city at a height of 80 meters at its height at the end of “Summer”, and then receding during “Spring”. This means that these waters move around 13 meters, up and then down, per hour.
Over the last 2,000 years, these floodwaters have risen about a meter per year, submerging a full 2 km of city. This slow encroachment, combined with spore-driven nocturnal euphoria, has reinforced a cultural drift toward night-obsession.