Ainu cosmology commonly pairs the sea and the mountain as the two great sources of subsistence, each governed by its own kamuy, and Repun Kamuy's position as the ocean's provider sits opposite Kim-un Kamuy's position as the mountain's. The pairing is not merely geographic convenience; oral literature and ceremonial practice both treat the two domains as complementary halves of a single provisioning relationship between the Ainu and the kamuy world; a community's wellbeing depended on maintaining good relations with both the kamuy of the mountains behind a settlement and the kamuy of the sea in front of it.
Because whaling and coastal fishing were practised by only some Ainu communities, chiefly those in coastal Hokkaido and Sakhalin, Repun Kamuy's prominence in a given community's oral tradition and ceremonial calendar varied considerably with how much that community's subsistence actually depended on the sea, in the same way inland communities more centred on mountain hunting gave correspondingly greater ceremonial weight to Kim-un Kamuy. The atlas records Repun Kamuy as part of a living tradition maintained unevenly across different Ainu communities today, following the same revival that has restored ceremonies such as iyomante in some places after a long period of administrative suppression.