Which countries in the world have mercenaries?

Modern mercenaries, the four largest mercenary companies in the world, are no longer stragglers like in the past, but set up companies according to modern business models, establish company management systems and undertake business. Externally, they generally call themselves employees of private armed companies or security companies. There are hundreds of companies established by mercenaries, of which four are more famous. First, the South African Private Armed Company (EO) established by 1989 had more than 700 members, most of whom were retired officers and special operations soldiers of the South African army. The company was involved in civil wars in Angola and other African countries. Later, due to strict management in South Africa, the company was dissolved a few years ago, and members either formed another company or joined overseas mercenary companies. The second is SI Company registered in Bahamas, with several offices in London and Washington. Founded in the early 1990s, the company has a British government and military background, and its employees include a number of senior British and American officers. Its main business is to provide security, consultation, military training, intelligence support and logistics support. The third company is MPRI, a military professional resource company located in Virginia, USA. It was founded by American general Lewis in 1987, and attracted many retired American generals to join it. It is reported that there are more than 2,000 retired soldiers in MPRI's file. The fourth is Blackwater Security Consulting Company, headquartered in the United States. Founded in 1996, the company has five subsidiaries, which provide consulting, training and information services respectively. The company has offices all over the world and a training camp in North Carolina. Its main customers are the State Council, Ministry of National Defense, Ministry of Communications and Department of Homeland Security, as well as famous multinational companies.