There were many common terminal illnesses in web novels. The following were some common types of terminal illnesses: 1. Heart disease: Heart disease is one of the most common incurable diseases, including high blood pressure, cardiovascular disease, cardiac arrest, and so on. Heart disease patients may have a heart attack and eventually die when their condition worsened. 2. Cancer: Cancer is another common terminal illness, including breast cancer, lung cancer, Prostate cancer, stomach cancer, and so on. Cancer cells can metastasize to other parts of the body and cause serious health problems and death. <strong></strong> Liver virus infection can cause damage to liver cells and eventually lead to liver failure. 4. AIDS: AIDS is an immune deficiency virus infection that may cause the immune system to be unable to effectively attack the pathogen, resulting in infection and disease. Kidney failure: Kidney failure is the result of kidney failure, which can lead to an imbalance of the kidneys, loss of protein, and other health problems that can eventually lead to death. Terminal diseases of the nervous system: Terminal diseases of the nervous system include brain tumors, multiple stiffen, stroke, and so on. These diseases may cause damage to the nervous system and functional failure. Understanding these types of terminal illnesses when writing a novel could help the author better portray the pain and struggle of the patient, and at the same time, make the story more realistic and touching. However, when writing a novel, one should also be careful not to use too extreme or fictional terminal illnesses to avoid discomfort for the reader.