As a forenote to the Ainu legend, it might be useful to know Kim-un Kamuy, the Ainu god of bears and mountains and to suggest here that the reason why there are so many Kims in Korea may be that as related to the broad swathe of arctic circum-polar regional peoples who venerated the bear and held bear festivals the Altaic Koreans in prehistoric times considered themselves the descendants of the ‘Kim’-bear, in the same way that the name ‘Kuma’ or ‘Kuma-no’ still denotes a relationship with a bear.
How it came to be that certain Ainu were descended from a brown bear
“In very ancient times there lived two people who were husband and wife. The husband one day fell ill and soon after died, leaving no children, so that the poor wife was left quite alone. Now it happened to have been decreed that the woman was at some future time to bear a son. When the people saw that the time for the child to be born was nigh at hand, some said, ‘Surely this woman has married again.’ Others said, ‘Not so, but her deceased husband has risen from among the dead.’ But the woman herself said that it was all a miracle, and the following is [her] account of the matter:
“‘One evening there was a sudden appearance in the hut in which I was sitting. He who came to me had the external form of a man and was dressed in black clothing. On turning in my direction he said, “O, woman, I have a word to say to you, so please pay attention. I am the god who possesses the mountains (i.e., a bear) and not a human being at all, though I have now appeared to you in the bodily form of a man. The reason of my coming is this. Your husband is dead, and you are left in a very lonesome condition. I have seen this and am come to inform you that you will bear a child. He will be my gift to you. When he is born you will no longer be lonely, and when he is grown up he will be very great, rich, and eloquent.” After saying this he left me.’
“By and by this woman bore a son, who in time really became a mighty hunter as well as a great, rich, and eloquent man. He also became the father of many children. Thus it happens that many of the Ainu who dwell among the mountains are to this day said to be descended from a bear. They belong to the bear clan, and are called Kim-un Kamui sanikiri—i.e., ‘descendants of the bear.'”
Source: Ainu Legends: Bear, NOVA Online
In Basil Hall Chamberlain’s “Aino Folk-Tales“, bears are depicted as trees turned into divine walking creatures.
Trees turned into Bears.
The rotten branches or roots of trees sometimes turn into bears. Such bears as these are termed payep kamui, i.e.“divine walking creatures,” and are not to be killed by human hand. Formerly they were more numerous than they are now, but they are still sometimes to be seen.—(Written down from memory. Told by Penri, July, 1886.)