I was playing Midieval 2 Total War, and one of my cities was hit with the Plague. I know that it wreaked havoc with the peasants/commoners, but was the royalty of Europe ever affected by the Plague, like an heir succumbing to the disease?
Of course they did. For example there's Anne of Bohemia who married Richard II of England for 12 years and died of plague. According to Agnes Strickland's Lives of the Queens of England from the Norman Conquest, Richard was devastated by her death and made many bad choices. The period until his overthrow was known as "Tyranny of Richard II" and eventually cost him his throne.
Other royal family members who died of the plague include Alfonso XI of Castile, Philip I, Duke of Burgundy, Blanche of Lancaster, Louis, King of Sicily, among others.