It could be about a hero who has faced some sort of downfall. Maybe the hero made a mistake, or was betrayed, and the visual novel explores his journey through this difficult time.
One key theme could be redemption. The fallen hero might be on a journey to redeem themselves for past mistakes. Another could be the loss of innocence, as they've fallen from their heroic status. And also, the struggle against society's expectations, since they are no longer the ideal hero but still have to face the world.
The story of the fallen knight hero, Tan, was mainly about a young man named Alan. He dreamed of becoming an excellent knight since he was young. By chance, he had obtained a legendary Knight's Guide. This book recorded in detail the skills and techniques that all knights had to master.
Under the ridicule and pressure of his parents, Alan still insisted on his dream and worked hard to learn various skills. However, his fate was constantly suffering setbacks and tribulations. He was defeated by the enemy in a battle and lost everything, including his dream and confidence.
However, Alan did not give up. He began to look for other knights and train with them. Through tireless efforts and hard training, he finally became an outstanding knight and won the respect and honor of the people.
In the end, Alan successfully realized his dream of becoming a great knight, and his story became a legend.
I'm not entirely sure how popular it is globally. It might be very popular within certain niche communities that are into this type of light novel, but it may not be as well - known as some mainstream bestsellers.
I'm not sure exactly, but it probably has the fallen hero as one of the main characters. There might also be characters who were once friends or allies of the hero and now have to deal with his fall.
One common theme is redemption. The fallen hero often has to find a way to make up for their past mistakes or misdeeds. Another theme is the loss of innocence. They have typically gone through some kind of trauma or made a bad choice that led them to fall from grace. Moral ambiguity is also a big one, as they may not be completely good or bad anymore.