There are 5 Vassal Families, and thus 5 clans of Vampires in the Prince's Kingdom. The Morelocks, the Sangreys, the Bloodworths, the Vondraks, and the Le Vrai.
The Morelocks are the newest Vassal Family, given their status only 60 years ago, to help stave off the former Necromancer Prince's military losses. As humans, they are as sickly as any of the Vassals, and disrespected by the others, as any aristocrat would disrespect a "nouveaux riche". As a family, they are the ones most tolerant of the Grand March in their country, and have tied their political futures with the success of this endeavor. If the March becomes a long term situation, then the Morelocks have much to gain. If not, they may have their title stripped from them. As Vampires, the Morelocks are almost idealistic, able to cast off their illnesses and do things never before possible, without the harsh attitude of older vampires to press upon them. They are most likely to brave the pain of the dim sun in order to accomplish a goal, just because they can.
The Sangreys on the other hand, are the oldest of the Vassal Familes, and the healthiest, forming an ironic mirror to the Morelocks. As humans, they serve the longest before being "recruited" into the Guard, serving as his human military, who end up serving the garrison of his palace and the capital city. As Vampires, they prefer quiet, calculated actions with as little effort as possible, delegating and manipulating. The current Elder of the Elite Guard is a Sangrey, and while he does not approve of the invitation to the Grand March, he respects the cunning and manipulation involved. Your average Sangrey is incredibly arrogant, seeing humans as livestock, to be nourished, guarded, and harvested.