This is a Hawaiian legend dealing with the unification of the Hawaiian Islands.
There was a king on the largest island in Hawaii who wanted to conquer all the other islands so he went island by island conquering and leaving a bloody trail behind him as the other kings resisted. On Oahu the king from the large island was victorious and he drove the enemy army off a cliff at what is now known as the Pali Lookout. Because of the gruesome nature of their deaths though some of the spirits of that army continue to linger in the area. While not seen by all, there are some who claim to have seen spirits there and have felt their presence.
This story is based in truth as king Kamehameha did in fact conquer all the Hawaiian Islands. This shows that the story has been around for some time. There wasn’t much told about what the spirits do, but because it was a violent death there is a negative stigma attached. This legend is particular to the island as each islands story of being conquered would be different. This means that while the conquering of the islands unified them it still had some elements that made each island distinct with certain items of folklore like this one.