The Twelve Kingdoms: The Vast Spread of the Seas

The Vast Spread of the Seas (Sea God in the East, Vast Sea in the West, 東の海神 西の滄海) is the third book in The Twelve Kingdoms fantasy series written by Fuyumi Ono. The English-language edition was published by Tokyopop on March 2009 as Hardcover under its PopFiction imprint.

Plot introduction
When only an eggfruit, the kirin of the En Kingdom, Rokuta, was transported to Japan for his own protection. But he was abandoned soon after birth by his surrogate parents, left to fend for himself in the mountains. It just so happened that at the same time, a young boy in the En Kingdom named Koya was also abandoned by his own parents, after which he was raised by demon beasts. Their similar circumstances aren't the only thing to bind these two boys, though. Twenty years after their abandonment, their destinies intersect, with potentially disastrous consequences for the En Kingdom.