The Dark Walks are a set of six large tunnels that link the six Koro to Mangaia.
The Walks were dug by Rahkshi as part of a ploy by Makuta to blackmail the Toa Maru into surrender; they are wide enough for several Rahkshi to march abreast and were used as such when Makuta's Rahkshi legions moved into place prior to the final battle.
Following Makuta's defeat, the Dark Walks became the main thoroughfare between the villages and the now-empty lair. They are infested with Rahkshi and Kraata, and instill a sense of dread and fear in beings who enter them. All the villages either monitor or actively guard their respective Dark Walk entrance.