From Blissful Sin:

Even before he was born it had been decided that the heir of the Haku Family, Reion, would be betrothed to the youngest child of the Koku Family, Kaen. For his coming-of-age and wedding ceremony, Reion visits the House of the Koku Family. However, Reion was no longer the boy he first saw in pictures, but a man overflowing with confidence. Furthermore, Reion left the words "I am as appalled as you are about this wedding between two men."