A king rode unicorns in Korean legend?!? Why did I not know of this before? I find this especially interesting because in the Korean graphic novel series Bride of the Water God by Mi-Kyung Yun there is a character called Lynn, who appears to be a unicorn. In fact, he has two forms. In one, he is a winged unicorn. (He looks like a horse but with more of a cow's tail). In his other form, he looks like a human, but with pointed ears and a unicorn-like horn in the middle of his forehead. He is ridden in his horse form by another character, Huye.
According to the Guardian, Korean unicorns are called kirins or qilins. They are described either as a 4-legged beast with a dragon's head (doesn't sound much like Lynn) or having the body of a deer, the tail of a cow, hooves and a mane. (Now that sounds much more like Lynn, doesn't it?)
Interestingly, when I looked up kirin in the Encyclopedia Mythica, it had this to say:
"Kirin. The Japanese unicorn, an animal-god who punishes the wicked with its single horn. It protects the just and grants them good luck. Seeing a kirin is considered an omenn of extreme good luck - if one is a virtuous person." (By Micha F Lindemans)
So the kirin is common to Japan and Korea at least. Interestingly, in one of the Tales of the Otori books by Lian Herne, a giraffe is brought to Japan and they refer to it as the kirin.
Any professors of East Asian studies out there? I would love to know more...