Miyabi was assigned to marry Mizore in the Snow Village. He "dirtified" Mizore by kissing her, leading her to contemplate suicide. Miyabi later appears to stops the fight between Kalua and Moka, cancelling Kalua's orders to kill everyone present because Kalua would have been at risk of dying from her injuries even if she won, had the fight continued. (Source: Wikipedia)

Spoiler

In volume 12 chapter 65, it is shown that Miyabi is actually the Shinso (True Ancestor) Alucard.