The Queen of Éirigh can arise from any class, though she is commonly either a Noble or the daughter of a Laird. The King alone can select and appoint his Queen through marriage. The power the Queen holds is determined between herself and the King, and has looked very different across the years.
The responsibilities of the Queen have varied vastly throughout the history of Éirigh. In the reign of the The Slánaitheoir Royal Family, she often took a very active role in the ruling of the kingdom, whether that be assisting the Royal Clerk in managing the Palace, or acting as the primary ambassador to foreign nobility. However, in The Máirtín Royal Family, the title is primarily ceremonial.