After the Yogoese people migrated to the Nayoro Peninsula, the Yogoese began to dominate the area and established the New Yogo Empire. The Yaku were reduced to an ethnic minority and retreated to rural areas of the peninsula, many of them residing in remote villages.
Many of the Yaku are greatly influenced by a strong belief in the supernatural world of Nayug and its connection to the natural world. Those with the strong ability to observe and communicate with the supernatural world, such as Torogai, can become shaman or magic weavers. Unlike the Yogoese, most of the Yaku history has been passed down through oral traditions, such as the stories of the birth of the water spirit.