Haemosu

Hae Mosu (hangul:해모수, hanja:解慕漱) was the founder and 1st Dangun of Buyeo. He is mentioned in the Hwandan Gogi, and Korean records of the 11th and 13th centuries that describe the founding of Goguryeo, one of the Three Kingdoms of Korea. Goguryeo considered itself a successor to Buyeo and annexed Buyeo remnants in 494.
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[Korean] Sun deity, son of the god of heaven, father of Chumong. Riding in his chariot, Oryonggeo, he descended from the heavens in the morning to hear the affairs of the people. When evening came, he ascended back into heaven. This descension-ascension cycle represents the rising and setting of the sun. Haemosu desired to take the three daughters of Habaek, a water deity, but only succeeded in taking the eldest, Yuhwa. When Habaek heard of this he was enraged that Haemosu did not follow the proper ceremony of marriage and brought disgrace to his house. An official ceremony was held, but the girl escaped before Haemosu could return to heaven. He later impregnated her through a ray of sunlight while she was in the king's household, and the child she bore was Chumong.