Hoori no Mikoto (Yamasachihiko)

Hoori, known as Yamasachihiko (Mountain-Luck Prince), is the hero of the Umisachi-Yamasachi tale. After losing his elder brother's fishhook, he journeyed to the palace of the sea god Watatsumi, where he married the sea princess Toyotamahime and received the lost hook along with magical tide-controlling jewels.

Returning to the surface world, he used the tide jewels to subdue his elder brother Hoderi. His wife Toyotamahime came ashore to give birth but asked him not to watch. When he broke this taboo, he saw her true form—a great sea creature (wani, interpreted as either a shark or crocodile)—and she fled back to the sea in shame, sending her sister Tamayorihime to raise the child.

Hoori's son Ugayafukiaezu married Tamayorihime, and their son was Jimmu, the first emperor. Thus Hoori stands as a crucial link in the genealogical chain connecting Amaterasu to the imperial dynasty.