The term 'Virus Fighter' refers to a person who works to protect against and fight viruses. This can be done through the use of a SERUM, which is a liquid containing antibodies that can be injected into the body to fight off a virus. An antibody is a protein produced by the body's immune system to fight off foreign substances such as viruses. By injecting a SERUM containing antibodies, a virus fighter can help protect against and fight off viruses.