Hand of the King is a powerful position within various courts. The Hand serves as the king's constant companion and asset - a most trusted and valuable friend. The Hand serves as king in his grace's stead when the king is not available to rule. The position was noted in many human cultures, some from other worlds far and wide.
The position's most common use was in Westeros and Hyrule. Ganondorf (Legends of Hyrule) was hand of the king before his descent into villainy.
As of current events, Link now serves as Hand of the King to King Rhoam Bosphoramus Hyrule.