The Kings and Queen of the Minor Arcana are very powerful figures. The Queens are naturally linked to the Empress, and the Kings to the card of the Emperor. They can give more information about these 2 cards in a reading. The Empress with the Queen of Wands is likely going to be a person with an emotional bound to the sitter for example. An Emperor and the King of Wands will relate to the work or social life of our sitter. This is simplified of course, but often true nevertheless.
Today, all 8 Kings and Queens in the deck tend to be seen as mostly positive figures. It's interesting to note that it was not always the case. Tarot finds its roots in the Middle Ages. A time where women were suspicious creatures, often seen as temptresses, witches and sinners of all kinds. Queens were more contrasted cards.
Some see the Queens as more powerful. Just like in Chess, the game is lost if the King is taken, but the one truly powerful warrior at play really is the Queen. I personally tend to see it that way too.
Let's have a look at the general characteristics of the Kings and Queens of the minor arcana, as they are currently used in most decks.
As we just reminded ourselves, the Tarot tradition goes back to the Middle-Ages in Europe. We can't forget what important role Kings and Queens played back then. Kings were considered divine for centuries. They were guides, fathers of the 'nation, chosen by (the) God(s) to lead their people. Kings were, by default, positive figures. They guaranteed the stability of a Kingdom. They cared for security and justice and would protect the people from invasions and aggressions.
Unless surrounded by a negative spread or reversed, the King is always a strong positive figure in a Tarot spread. It often represents an important man in the questioner's life or the questioner himself if a man. The Kings of the minor suits also reflect a certain aspect or face of the Emperor in the deck.
The Queens are the feminine counterparts of the Kings. They are also a reflection or a certain aspect of the Empress. These cards are very strong and have a weight in a reading that is naturally superior to a page or knight for instance. Just like the Kings, they can become threatening when reversed.
But even when drawn upside, they're more complex and contrasted than the Kings. Mostly because in the Middle Ages, women were not only considered inferior to men, they were always a possible danger.
These aspects can be used or not in a reading depending on your culture, background but above all, the energy of the session you're in.
The Queens are always highly related to the practical intelligence. The intellect serving a true purpose.