He is also the father of Amaterasu, Tsukuyomi, Susanoo, and countless other gods and being the brother of the underworld goddess Izanami. Through Amaterasu, he is an ancestor of the Japanese Imperial family.
Izanagi also defends against the forces of Yomi, and ensures there are more births than deaths each day in order to preserve his creation. He often wields Ame-no-nuboko, the heavenly jeweled spear with which he churned the primordial seas.
He is the father of many Shinto rituals as well, including marriage and Misogi. The latter ritual is central to Shinto beliefs and uses water to wash away impurities, such as the death and rot Izanagi encountered while in the underworld.
As father to the chief gods of Heaven, Izanagi was the original ruler of Heaven and trained his daughter Amaterasu to take the throne. While he still maintains some authority, Izanagi has bequeathed most of his power to Amaterasu, who now serves as the true ruler of Heaven.
Birth of the Lands
Izanagi and his sister-wife Izanami are the seventh generation of Kamiyonanayo and the children of Omodaru and Kashiko-ne. From the void came Heaven and Earth, but in the beginning, however, only Heaven was populated. Seeing that Earth was untouched, the primordial deities gave their blessings to Izanagi and Izanami to fill it with life. Together with Izanami, the Female Who Invites, they were given the task of creating the world.
Standing at the pillars of heaven, the siblings used the spear Ame-no-Nuboko to churn the sea, and from this churning came the first islands of Japan. In the wake of this achievement, the two saw their bodies complemented one another, and Izanagi proposed to Izanami so they might procreate. Izanami agreed, and the two began to prepare for the marriage ceremony. Standing on Ama-no-Ukihashi, the floating bridge of the heavens, they plunged a jewel encrusted spear into the ocean. When they pulled it free, the water that dripped from the spear coagulated and formed the first island of the Japanese archipelago.
Izanagi and Izanami performed the first marriage ceremony by walking around the pillars of heaven and meeting in the center. In the initial ceremony, Izanami spoke first; this was out of line, however, and caused the marriage to be improperly sealed. The children born of this union were illegitimate and deformed as a result. They performed the marriage ceremony once more, this time with Izanagi speaking first. With their marriage sealed properly this time, Izanagi and Izanami gave birth to the remaining Japanese islands as well as a host of gods - the first legitimate kami.
Descent into Yomi
They drew the islands of Japan from the sea; in this way, the two deities effectively gave birth to the islands, which in turn are considered to be their children. The islands in this creation myth are generally thought to be Kyushu, Shikoku, and Honshu, as well as the smaller islands that surround them. Izanagi then fathered the first great generation of kami, culminating in the birth of the fire god Kagutsuchi, who killed Izanami.
Here the first gods and humans were born. When his wife died giving birth to Kagutsuchi and burning her severely, Izanagi went to the underworld to retrieve her. Izanagi set out for Yomi-no-Kuni, the Land of the Dead. This land was defiled and impure, full of demons and other monsters. When Izanami died, Izanagi tried to retrieve her from the underworld, but failed. He mistakenly looks at her while she's in a rotting, monstrous state in the underworld, which shames her and she attempts to kill him. Knowing Izanami would devour the world if she escaped Yomi, Izanagi placed a giant boulder at the mouth of the underworld in order to prevent her return. Furious, Izanami cursed the world, saying she would kill a thousand people each day. Izanagi responded by vowing one thousand five hundred people would be born each day.
When Izanagi returned from the underworld, he started the first cleaning rites. He washed his left eye and thus created the sun goddess Amaterasu. When he washed his right eye, the moon god Tsukuyomi came forth. From his nose he created Susanoo, the god of the seas and the storms. He is the father of countless kami and the bureaucracy of the heavens, over which his daughter, the sun goddess Amaterasu, presides.