Mr. Kim, the ancestor of Young Yoo, was a friend of Bari and Damseol long into the past, originally knowing the both of them while they trained to become dragons. His life was one of pain and misery, but he did his best to hide that from Bari.
In the end, Mr. Kim was responsible for Bari failing to ascend, as he intentionally caused him to fall so that Damseol would be able to have a river instead. His true intentions for this were never known, but he lied and said it was out of love for Damseol. He jumped off a cliff and took the answers with him forever.
Content compiled by AnimeList.moe from publicly available sources.
