This question involved many aspects such as culture, history, and imagination. In traditional Chinese culture, a big beard was considered a symbol of loyalty and bravery. In addition, because only men in ancient times usually had beards, this image was also adopted by men. In novels, this image was often used to describe the appearance of loyal officials and generals to emphasize their sense of responsibility and loyalty. The physical characteristics of these characters could also be used to show their bravery and determination, making them more memorable and believable. It is important to note that different novels and cultural works may use different ways to portray different types of loyal generals in some novels.