The Maintenance Tunnels

The Maintenance Tunnels were the underground service network running beneath the city of Metru NuiMetru NuiThe city beneath Mata Nui functions as the Great Spirit's brain, housing the Matoran whose labor keeps the god alive., centred under Onu-MetruOnu-MetruThe deep archive-city that made mining and historical records preservation the beating heart of Metru Nui. and extending through the foundations of the surrounding districts. Their principal function was the upkeep of the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface. and the routing of utility infrastructure, but their layout was so complex that they acquired the nickname Fikou WebFikou WebThe maintenance tunnel system beneath Metru Nui's Archives, named for how its paths twist like spider silk. after the spider RahiRahiThe Rahi were the biomechanical wildlife of the Matoran Universe, built largely by the Brotherhood of Makuta, ranging from background fauna to engineered war beasts. that nested in their passages. The tunnels were maintained by the ArchivistArchivistA Matoran keeper of records and relics, the Archivist held one of Metru Nui's deadliest jobs. Corps and patrolled in part by VahkiVahkiMetru Nui's mechanical law enforcement squads, designed to maintain rigid order but ultimately undermined by chaos beyond their programming. RorzakhRorzakhThe Vahki model assigned to Onu-Metru, the Rorzakh were utterly relentless and carried Staffs of Presence that turned the affected Matoran into an involuntary audio and visual transmitter for their squad., and they were used by the Toa MetruToa Metru and Toa HordikaSix Matoran elevated by Lhikan to save their city, mutated by Visorak venom, and restored in time to deliver the population to safety. as the escape route through which the surviving MatoranMatoranThe most abundant species in the Matoran Universe, chosen by Mata Nui to inhabit and maintain his cosmic body. were carried out of the city after TeridaxTeridaxTeridax orchestrated a thousand-year scheme that ended with him occupying the Great Spirit Robot itself before his death on Bara Magna.'s coup.

Layout and the Fikou WebFikou WebThe maintenance tunnel system beneath Metru Nui's Archives, named for how its paths twist like spider silk.#

The Maintenance Tunnels formed a dense lattice of corridors beneath Onu-MetruOnu-MetruThe deep archive-city that made mining and historical records preservation the beating heart of Metru Nui. and ran outward through the foundations of the city. The network took its nickname from two related features: the webs left in the passages by the FikouFikouSmall arachnid Rahi associated with Metru Nui's Maintenance Tunnels, the reason the tunnel network earned the nickname Fikou Web. spider RahiRahiThe Rahi were the biomechanical wildlife of the Matoran Universe, built largely by the Brotherhood of Makuta, ranging from background fauna to engineered war beasts. that lived in the tunnels, and the web-like geometry of the corridors themselves, which branched and crossed without an obvious central axis. The complexity made the system difficult to map fully, and even the ArchivistArchivistA Matoran keeper of records and relics, the Archivist held one of Metru Nui's deadliest jobs. Corps relied on landmarks and personal familiarity rather than on a unified plan.

Hatches set into the corridors connected the tunnels to the surface and to the lower levels of the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface.. Pipes ran along certain stretches of the network and carried molten ProtodermisProtodermisThe engineered substance building the Matoran Universe, protodermis exists in countless refined states from mundane metal to diamond-hard crystal to the destruction-or-transformation force of energized form. outward to heat the rest of the city, which made the tunnels part of Metru NuiMetru NuiThe city beneath Mata Nui functions as the Great Spirit's brain, housing the Matoran whose labor keeps the god alive.'s utility infrastructure as well as part of its maintenance plant. Other corridors led to secured destinations entirely outside the city's normal civic geography. A passage from the maintenance network connected to the Prison of the Dark HuntersPrison of the Dark HuntersA covert detention site near the border of Po-Metru and Onu-Metru, used by Nidhiki and Krekka during their stint as Metru Nui enforcers and the cell where Lhikan mentored three future Toa Metru., a facility guarded under normal conditions by VahkiVahkiMetru Nui's mechanical law enforcement squads, designed to maintain rigid order but ultimately undermined by chaos beyond their programming. RorzakhRorzakhThe Vahki model assigned to Onu-Metru, the Rorzakh were utterly relentless and carried Staffs of Presence that turned the affected Matoran into an involuntary audio and visual transmitter for their squad., and another opened onto a gateway leading to the Canyon of Unending Whispers.

Sections of the FikouFikouSmall arachnid Rahi associated with Metru Nui's Maintenance Tunnels, the reason the tunnel network earned the nickname Fikou Web. Web contained large doors and sealed chambers whose contents were not catalogued in the public Archives index. The combination of working service tunnels, restricted access corridors, and uncharted side passages meant that the network functioned as a buffer zone between the ordered city above and the older, less regulated geography below it.

Resident fauna#

The tunnels were home to several RahiRahiThe Rahi were the biomechanical wildlife of the Matoran Universe, built largely by the Brotherhood of Makuta, ranging from background fauna to engineered war beasts. species that exploited the warmth from the heating pipes, the cover of the corridors, and the proximity to the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface. above. FikouFikouSmall arachnid Rahi associated with Metru Nui's Maintenance Tunnels, the reason the tunnel network earned the nickname Fikou Web. spiders nested in the upper reaches of the network and left the webbing that gave the system its nickname. Kuma-NuiKuma-NuiGiant rat-like Rahi that haunted Metru Nui's Archives before fleeing to Mata Nui., large rat-like RahiRahiThe Rahi were the biomechanical wildlife of the Matoran Universe, built largely by the Brotherhood of Makuta, ranging from background fauna to engineered war beasts., lived in the maintenance tunnels of the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface., particularly in the sections beneath Ta-MetruTa-MetruThe fire district where Ta-Matoran perfected their craft and powered Metru Nui's industry for thousands of years. and Ko-MetruKo-MetruKo-Metru was Metru Nui's frozen intellectual quarter, home to the scholarly Ko-Matoran race., and many of them later migrated to the Ta-WahiWahiThe Matoran word for region. The six Wahi of Mata Nui were the six elemental territories that made up the island before the Bohrok cleared its surface. and Onu-WahiWahiThe Matoran word for region. The six Wahi of Mata Nui were the six elemental territories that made up the island before the Bohrok cleared its surface. regions of the island above when the population evacuated.

Fireflyers nested in the furnaces and in the maintenance tunnels beneath Ta-MetruTa-MetruThe fire district where Ta-Matoran perfected their craft and powered Metru Nui's industry for thousands of years.. The insects were docile when left undisturbed but turned vicious when angered or threatened, and a swarm in a confined corridor could cause serious harm to anyone caught in the open. The KarzahniKarzahniA region of the Matoran Universe built by the Great Beings as a Matoran repair facility, ruined by the failures of its overseer. plant, created by TeridaxTeridaxTeridax orchestrated a thousand-year scheme that ended with him occupying the Great Spirit Robot itself before his death on Bara Magna. and named after KarzahniKarzahniBionicle reused one cursed name three times, and every instance earns it, this is the article that finally untangles all three. as a private joke, was sent deep into the maintenance tunnels after it proved too willful for its intended purpose, and its presence in the lower passages was one of the hazards that the ArchivistArchivistA Matoran keeper of records and relics, the Archivist held one of Metru Nui's deadliest jobs. Corps did not advertise.

The combination of insect swarms, predatory mammals, spider webbing, and the occasional discarded experiment meant that descent into the deeper tunnels was not undertaken casually. The Archivists who worked in the network operated under standing precautions, and the VahkiVahkiMetru Nui's mechanical law enforcement squads, designed to maintain rigid order but ultimately undermined by chaos beyond their programming. RorzakhRorzakhThe Vahki model assigned to Onu-Metru, the Rorzakh were utterly relentless and carried Staffs of Presence that turned the affected Matoran into an involuntary audio and visual transmitter for their squad. patrols that monitored the prison corridor were assumed to provide a degree of cover for the surrounding routes.

NuparuNuparuAn Onu-Matoran engineer from Metru Nui who built the Boxor and rose to become a Toa of Earth despite no warrior destiny. and the sea leak#

The most fully documented expedition into the tunnels began when the Onu-MatoranOnu-MatoranEarth-wielding Matoran of the deep who adapted to darkness and built the Matoran Universe's defensive cavalry. NuparuNuparuAn Onu-Matoran engineer from Metru Nui who built the Boxor and rose to become a Toa of Earth despite no warrior destiny. approached the Toa MetruToa Metru and Toa HordikaSix Matoran elevated by Lhikan to save their city, mutated by Visorak venom, and restored in time to deliver the population to safety. with a report of a leak in the maintenance corridors beneath the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface.. The walls in the lower tunnels were normally reinforced by the Onu-MatoranOnu-MatoranEarth-wielding Matoran of the deep who adapted to darkness and built the Matoran Universe's defensive cavalry. miners, and a leak from the surrounding sea was therefore unusual enough to warrant immediate attention. WhenuaWhenuaToa Metru of Earth and later Turaga of Onu-Koro, formerly an Onu-Metru archivist whose career in the Archives shaped his role across the rescue of Metru Nui and the long residency on Mata Nui., who had served as an ArchivistArchivistA Matoran keeper of records and relics, the Archivist held one of Metru Nui's deadliest jobs. before his transformation, agreed to lead the investigation.

The ToaThe Toa: Heroes of the Matoran UniverseThe Toa were biomechanical guardians sworn to protect the Matoran, bound by a strict code and defined by sacrifice across every age of the universe. entered the network through a hidden shortcut that WhenuaWhenuaToa Metru of Earth and later Turaga of Onu-Koro, formerly an Onu-Metru archivist whose career in the Archives shaped his role across the rescue of Metru Nui and the long residency on Mata Nui. opened by breaking a hole in the road above. The shortcut bypassed the standard entry hatches and brought the group directly into the Fikou WebFikou WebThe maintenance tunnel system beneath Metru Nui's Archives, named for how its paths twist like spider silk.. The descent was almost immediately complicated by a freak fog and the buzz of a FireflyerFireflyerInsect Rahi of Ta-Metru that swarm with lethal stings when provoked. swarm. MatauMatauA former Le-Metru test driver who became a Toa Metru, Matau wielded air, illusion, and shape-shifting before sacrificing his Toa power to wake the sleeping Matoran., using what little elemental power he had at that early stage of the Toa MetruToa Metru and Toa HordikaSix Matoran elevated by Lhikan to save their city, mutated by Visorak venom, and restored in time to deliver the population to safety.'s development, blew the fog aside long enough for the group to continue. The expedition, recorded in The Darkness BelowThe Descent into the Fikou WebAn expedition by the Toa Metru into the maintenance tunnels beneath Onu-Metru to investigate a seawater leak, ending in their first encounter with the shape-shifting Rahi Krahka., set the pattern for the Toa's later movement through the tunnels, in that the network's RahiRahiThe Rahi were the biomechanical wildlife of the Matoran Universe, built largely by the Brotherhood of Makuta, ranging from background fauna to engineered war beasts. hazards proved as significant as its structural ones.

The escape route#

After TeridaxTeridaxTeridax orchestrated a thousand-year scheme that ended with him occupying the Great Spirit Robot itself before his death on Bara Magna.'s coup and the imprisonment of the MatoranMatoranThe most abundant species in the Matoran Universe, chosen by Mata Nui to inhabit and maintain his cosmic body. population in spheres beneath the ColiseumThe ColiseumCentral tower of Metru Nui, serving as government seat, sporting arena, and, during Teridax's masquerade, a prison for the city's Matoran population., the Toa MetruToa Metru and Toa HordikaSix Matoran elevated by Lhikan to save their city, mutated by Visorak venom, and restored in time to deliver the population to safety. used the maintenance tunnels as part of the route through which the recovered spheres were carried out of the city. The ArchivistArchivistA Matoran keeper of records and relics, the Archivist held one of Metru Nui's deadliest jobs. passages and the lower service corridors connected the central districts to areas of the Great BarrierThe Great BarrierThe enormous underground dome of rock and solid Protodermis that enclosed Metru Nui and the Silver Sea, sealed Teridax into a cliff face, and was finally cracked open during the Great Cataclysm. that were not under direct surveillance, and the tunnels' irregular geometry made them difficult for VahkiVahkiMetru Nui's mechanical law enforcement squads, designed to maintain rigid order but ultimately undermined by chaos beyond their programming. patrols to sweep efficiently.

The ToaThe Toa: Heroes of the Matoran UniverseThe Toa were biomechanical guardians sworn to protect the Matoran, bound by a strict code and defined by sacrifice across every age of the universe. hijacked a Vahki TransportThe Vahki TransportThe multi-legged cargo vehicle built by the Vahki of Metru Nui and used by the Toa Metru to escape the city across the Silver Sea after the Great Cataclysm. and christened it the LhikanLhikanToa of Fire, leader of the Toa Mangai, and the last Toa of Metru Nui, who surrendered his Toa Power to create the Toa Metru and died defending Vakama., and the recovery of the MatoranMatoranThe most abundant species in the Matoran Universe, chosen by Mata Nui to inhabit and maintain his cosmic body. spheres from storage tunnels formed part of the same operation. The maintenance network provided the cover required to move spheres from the ColiseumThe ColiseumCentral tower of Metru Nui, serving as government seat, sporting arena, and, during Teridax's masquerade, a prison for the city's Matoran population. area through to the points at which the Toa's improvised transport could carry them. The escape ultimately led through the Great BarrierThe Great BarrierThe enormous underground dome of rock and solid Protodermis that enclosed Metru Nui and the Silver Sea, sealed Teridax into a cliff face, and was finally cracked open during the Great Cataclysm. and out onto the Silver SeaThe Silver SeaThe vast body of unrefined liquid Protodermis surrounding Metru Nui inside the Great Barrier dome of the Matoran Universe., but the underground stage of the journey relied on the Fikou WebFikou WebThe maintenance tunnel system beneath Metru Nui's Archives, named for how its paths twist like spider silk. and on the routes that WhenuaWhenuaToa Metru of Earth and later Turaga of Onu-Koro, formerly an Onu-Metru archivist whose career in the Archives shaped his role across the rescue of Metru Nui and the long residency on Mata Nui. and the ArchivistArchivistA Matoran keeper of records and relics, the Archivist held one of Metru Nui's deadliest jobs. Corps knew best.

After the Cataclysm#

The Great CataclysmThe Great CataclysmThe day Makuta Teridax put the Great Spirit to sleep, the Great Spirit Robot fell from the sky, Metru Nui flooded, and Voya Nui tore loose from the Southern Continent. broke open the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface. and damaged the supporting structure of the maintenance corridors. Many stasis tubes shattered in the levels above, releasing RahiRahiThe Rahi were the biomechanical wildlife of the Matoran Universe, built largely by the Brotherhood of Makuta, ranging from background fauna to engineered war beasts. into the upper tunnels and complicating any later attempt to map the surviving network. The released specimens mixed with the original tunnel fauna, and the corridors that had previously been used for routine maintenance became significantly more dangerous to traverse. Kuma-NuiKuma-NuiGiant rat-like Rahi that haunted Metru Nui's Archives before fleeing to Mata Nui. populations dispersed to the surface in the migrations that followed, although a residual presence remained in the warmer sections of the tunnels.

The Staff of ArtakhaArtakhaArtakha was the master craftsman of the Matoran Universe, ruler of a hidden island, and the forger of the Toa Mata, the Avohkii, and the Kraahkan. was eventually used to restore Metru NuiMetru NuiThe city beneath Mata Nui functions as the Great Spirit's brain, housing the Matoran whose labor keeps the god alive. and rebuild the damaged walls of the ArchivesThe Archives of Metru NuiThe Archives of Onu-Metru were the central repository of Matoran knowledge and Rahi specimens, maintained by the Archivist Corps beneath the city's surface.. The maintenance network was repaired as part of the same restoration, and the Toa HagahToa HagahElite Toa teams appointed by the Brotherhood of Makuta to serve as personal guardians, later rebelling against their creators. oversaw the stabilisation of the surrounding Onu-MetruOnu-MetruThe deep archive-city that made mining and historical records preservation the beating heart of Metru Nui. infrastructure. Not all sections were fully resecured, and the connections to the Prison of the Dark HuntersPrison of the Dark HuntersA covert detention site near the border of Po-Metru and Onu-Metru, used by Nidhiki and Krekka during their stint as Metru Nui enforcers and the cell where Lhikan mentored three future Toa Metru. and the Canyon of Unending Whispers gateway were left in an uncertain state. When the surviving population eventually resettled on Spherus MagnaSpherus MagnaA desert world of ancient conflict that became the merger point of the Matoran Universe and Bionicle's true endpoint., the maintenance tunnels were abandoned along with the rest of Metru NuiMetru NuiThe city beneath Mata Nui functions as the Great Spirit's brain, housing the Matoran whose labor keeps the god alive., and the Fikou WebFikou WebThe maintenance tunnel system beneath Metru Nui's Archives, named for how its paths twist like spider silk. ceased to be maintained.