Ohkuninushi, the lord of the land, decided to give his land to the highest goddess, Amateras. Amateras sent a god Hononinigi to reign the land and he became the ancestor of Japanese emperors. Hononinigi fell in love with a beautiful princess, Konohanano-Sakuya-Hime and asked her father Ohyamatsumi for their marriage. Ohyamatsumi sent Konohana's sister Iwanaga-Hime along with Konohana to make both of them his wives. However, Hononinigi didn't like Iwanaga because she was so ugly. She was sent back to her father Ohyamatsumi and he got so angry. "I sent my two daughters to you because Konoyaha would bring you prosperity and Iwanaga would have brought you enernal life but you rejected Iwanaga. You and your descendents lost the chance to live forever." This is why gods (and emperors) die on our land.
Konohana, a flower princess was the symbol of prosperity and Iwanaga, a rock princess represented eternal life.