The first gods Kunitokotachi and Amenominakanushi summoned two divine beings into existence, the male Izanagi and the female Izanami, and charged them with creating the first land. Having given the lovers a bejeweled spear, they created the first island by letting drops from the spear mix within the ocean below them and thus “Onogoroshima” became their first.
They decended down to this island and made it their home. Because they wanted to marry and mate they built a pillar and then a castle around the pillar. When they circled the pillar and met eachother on the other side Izanami spoke first and Izanagi told her it wasn’t decent in such a time but they mated and Izanami gave birth to two children.
Both of which were deformed and not considered Deities. Rather more seen as devils. these were Hiruko (leech-child) and Awashima (faint-island). Izanagi and Izanami set the children on a boat and pushed them out to the sea. Pleading with the gods to tell them what went wrong. The gods told them, the male should have spoken in greeting before the female during the marriage ceremony. So they went around the pillar again and this time Izanami remained silent until her husband spoke first.
This deemed the marriage succesfull and they continued to have eight more children.
The eight great islands; Awaji, Iyo (later Shikoku), Ogi, Tsukushi (later Kyūshū), Iki, Tsushima, Sado, Yamato (later Honshū). The constant bubbles in the ocean created six more islands and many deities.
When Inazami gave birth to the fire god Kagutsuchi, She was badly burned and died. From her death many more gods were born, of which earth and water goddess’. Izagami, mourning the loss of his wife, created more deities aswell and in the anger of his mourning he beheaded his son Kagutsuchi and cut his body into eight pieces. Which became into eight vulcanoes. The blood dripping off Izanagi’s sword became a number of gods also.
Still not satisfied with his mourns Izanagi travelled to Yomi, the Japanese underworld, to find his wife and beg for her to return. He couldn’t see his wife’s appearance due to the shadows in Yomi and she declined him; saying she had already eaten the dark food of Yomi and was condemned to stay there. The news shocked Izanagi and refused to leave her but when she fell asleep he took the comb that bound his long hair back from his face and set it on fire he was so shocked to see Inazamis decomposing face and body. The beautiful woman that he loved was no longer. He couldn’t hold his fear and cried out and he ran away to return to the living and abandon his dead wife.
Inazami woke and shrieked, angry about him seeing her like that and chased him before setting out her son Raijin, god of thunder and rain and the hag Shikome after her husband to drag him back to Yomi.
Izagami burst out of the gate between the world of the living and the world of the dead and barricaded the entrance with a large boulder.
Izanami screamed at him from behind the boulder that she, for this, would take 1000 living residents each day. He replied telling her he would give life to 1500 each day.
And so death was introduced into the world but Izagami still fuels growth of mankind by giving more than Izanami.
When he returned he saw the filth of Yomi on his own body and began to cleanse himself . He created twelve new deities by undressing, five deities by washing, three by countering the evil. In the last step of the purification ceremony, Izanagi washed his left eye from which Amaterasu Ōmikami was born; washed his right eye from which Tsukuyomi-no-mikoto was born; and when washing his nose, Takehayasusanoo-no-mikoto was born.
After this they say Izagani retired and joined his daughter in heaven. Other say he laid to rest on the island of Honshy where he is still is worshipped.
Source; Wikipedia, Ancient Mythology .