The hereditary nobility, who were the ruling and military elite in the Middle Ages and the perceived elite afterwards. Whether or not they have a sovereign whom they are subordinate to, these characters have commoners who are subordinate to them. Their position is hereditary, often legally enforced, although occasionally simply socially accepted to the same effect.
Usually, the longer the family and its heritage have been known the better. In some periods and countries, it can carry the taint of being not quite noble yet if only one's parents were ennobled. Thus, nobles are often quite proud of the length of their lineage, which makes them the natural foil of the Self-Made Man. For the same reason young aristocrats are often quite powerless in the hands of The Patriarch who rules the family, making the threat of Passed-Over Inheritance quite powerful.
While there are often gradations in rank between them, the common trait of aristocrats is that, unlike the monarch, they are surrounded by their equals and if there is no monarch some form of power-sharing will be in effect with plenty of intrigue. Prone to Moral Myopia, Blue Bloods often regard only their class as important, which often leads to Aristocrats Are Evil. Insults between aristocrats result in Throwing Down the Gauntlet, or the Glove Slap, and a Duel to the Death, but an insult from a commoner results in the aristocrat's servants thrashing him, and an insult to a commoner hardly counts anyway (as a consequence, they are prone to underestimating the Powder Keg Crowd and setting it off).
Their effectiveness is frequently inversely related to their civilization. Dark Ages nobility often features Rank Scales with Asskicking, and the Middle Ages nobility will feature the Knight in Shining Armor and The Tourney, but a highly refined and civilized culture will feature an inordinate number of Upper Class Twits (though an Officer and a Gentleman is also possible) if not indeed decadent courtiers.
Normal feature of the Standard Royal Court and Decadent Court. Endemic in Historical Fiction, High Fantasy, and Feudal Future. Oddly enough, often characters who have been Made a Slave have former nobility as their Back Story. The Officer and a Gentleman is also often a Blue Blood, particularly if the noble code emphasizes the duties and responsibilities that come with noble birth. Even in peacetime, they may regard readiness for war a duty; hence, The Tourney. As with Royalty, the Ermine Cape Effect can apply, so many should be expected to wear extremely fancy clothes if possible. If culturally foreign from their subjects, can be a Foreign Ruling Class. Related character tropes are the Evil Chancellor, Gentleman Snarker, Regent for Life, Royal Brat, Upper-Class Twit, Proper Lady, Silk Hiding Steel, and Grande Dame.
Since the duty of the nobility in the Middle Ages was warfare, the sons of the nobility traditionally chose a military career. Even today sons of old noble families are over-represented in most military academies around the world. The word cadet for an officer trainee stems from French, meaning "younger": the eldest son inherited the manor and estate, and the younger sons went to military academies;note for a prime example of this, both Napoleon and The Duke of Wellington were younger sons of minor nobles (Napoleon was a second son, Wellington a third son). Tragically, since in the past the military education was begun at a very early age (7 to 11 years old), the nobility has also produced a lot of Kid Samurai, but also a lot of Child Soldiers. Today the old noble families are very likely to produce an Officer and a Gentleman.
The phrase ("blue blood") is a literal translation of the Spanish sangre azul. The idea, originating in medieval times, was that common folk would have to work outside all day, and would thus develop tans. The wealthy, on the other hand, could spend all day inside, which would keep their skin pale (as they were fair-skinned Europeans). This would make their wrist veins with 'blue' blood easily visible, hence the term. It's also been suggested that the term is race-based, since the pale-skinned European Spanish wanted to distinguish themselves from the darker-skinned "Moors". Yet another idea on the term's origin, which is erroneous but included here due to the likelihood of the reader encountering it in the context of nobility, is that crustaceans such as lobster literally have blue bloodnote and have always been very expensive. Thus, being able to afford these blue-blooded creatures would require considerable wealth, which usually meant noble station.note Another explanation could be that lobsters are heavily armoured — as a Knight in Shining Armor would be.
Super-Trope of Impoverished Patrician, Knight in Shining Armor, Remittance Man, Noble Fugitive, Aristocrats Are Evil and Officer and a Gentleman. Compare Royal Blood, Idle Rich, Old Money, Gentleman Snarker, and the upper echelons of the Fantastic Caste System (as well as real ones, like the traditional castes of India).
Not to be confused with blood that's literally blue; Black Blood or Alien Blood would cover that. Neither should it be confused with the television series Blue Bloods, although the title is a pun on this idiom.
