Civil cases are private matters, which typically involve one person suing another for a money award or a court order to make the other party do (or stop doing) a particular act.
Criminal cases involve wrongs against the public. Although a criminal defendant may have injured only one victim, any violation of criminal law harms society. Criminal cases are always started by the government. While victims of crimes may be consulted, they have no power to make a prosecutor bring charges or to prevent the prosecutor from dropping charges. A convicted defendant may be ordered to pay a fine, or may be sentenced to probation, community service, jail, prison, or even death.