Yoi is the principal civilizing hero of the Tikuna, the elder of the two brothers born from Ngutapa's knees and the prudent, deliberate counterpart to his brother Ipi. He is credited with the very origin of the Tikuna people, whom he fished from the reddened waters of the Eware creek with a baited line; the ones drawn out are the Magüta, 'those fished with a rod', a name the people still use for themselves. To the confused multitude he gave order, distributing them into clans and moieties by having each drink a cooked broth that revealed its affiliation, and decreeing that the two halves marry one another. He is further said to have felled the sky-darkening tree Wone, thereby instituting the succession of day and night and transforming its wood into the river system of the upper Amazon. Sources treat him at once as a creator deity and as the founding culture hero of ritual and social law.