For years, private armies have provided services to governments around the world. They are often secretive and operate in the shadows.
Blackwater - now known as Academi - is one of the most well-known private armies. It has provided troops and other services to the US government in different conflicts, including the Iraq war.
But it is not always clear how these private armies are formed, where they operate, or even what their missions consist of.
Eeben Barlow is chairman of 'Specialised Tasks, Training, Equipment and Protection International' - a private army that - according to Barlow - has operated throughout Africa and beyond. He was also behind another similar company that shut down in 1998 - called Executive Outcomes.
And while many argue private armies are mercenaries doing the jobs governments do not want to do - Barlow insists his operations are legitimate and follow international law.
"We don't see ourselves as mercenaries. We are first of all contracted by a national government. We become part of their armed forces, we wear their uniforms, we follow their procedures and guidelines, we fall under the legal regulations of that country. So, in other words, we serve the country that contracts us. And yes, we get paid for it, but we certainly don't get paid to run around and cause chaos," says Barlow.
Some private military contractors have been accused of prolonging conflicts instead of ending them, but Barlow believes that "there is a fine line between moral and immoral".
"But that really goes back to the people that are involved ... We've never prolonged a conflict, in fact, we've ended them despite them carrying on for decades and decades. We've ended them in a very short space of time. But I am aware of companies that do not mind if the conflict continues because that's the goose that lays the golden egg, and they certainly don't want to stop it," says Barlow.
He stresses the importance of cultural understanding and expertise needed to end conflicts across Africa.
"We are after all Africans that work in Africa. But I do think there is a major concern that Africans can actually end African conflicts," says Barlow.
"We look at all these private military companies going into Africa, they are just charging, they don't understand the environment they are in, they don't understand the area of operation, they don't understand the people and very quickly, they offend people ... If they are not going to add value and bring about ... stability and peace, then they shouldn't be there. But unfortunately, this has been allowed to drag on."
So who makes sure these armies are indeed following international law? How do they operate? And is there accountability?
Eeben Barlow provides an insight into the world of private military contractors as he talks to Al Jazeera about his company's role in fighting Boko Haram in Nigeria, the LRA in Uganda and other conflicts across Africa.
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