Mercenary, or Condottiero, is a person who comes into an armed conflict for their own economic benefit: for money or other tangible benefits.
In some cases, condottieri are not just mercenaries, but the leaders of professional military Free Companies. For example, King Esterad Thyssen of Kovir and Poviss released some political prisoners formerly known as the Sly cats on the condition that they support the efforts to push back the Nilfgaardian invasion at the battles of Mayena and Brenna.