I can recommend " I Play Mobile Games in the Three Kingdoms ". The protagonist of this novel is a mobile game otaku who traveled to the end of the Han Dynasty and became Liu Qi. In the game, he had experienced many battles and had always been committed to conquering the world. The plot of this novel is very interesting. It can satisfy your needs for the Three Kingdoms theme, and it also meets the requirements of a single person siege. I hope you like my recommendation.