[Untamed]

The legality of being a mercenary depends on whether the group you work for is a company with a Tax ID or not.

That's it.

Call it "security" or "military training" or "strategic consulting" or any other euphemism meaning "professional, paid soldier outside of a government-controlled organization", and you are essentially a mercenary. Blackwater and DynCorp are two very high profile "private security" companies that employ former military personnel from many countries. They also possess some of the most sophisticated equipment and military hardware available to any organization; some say, its too sophisticated for anyone outside of the US Military.