Ravages of Time - Dian Wei's presence

A mirror improves the ability to think. Some people avoid to look at the mirror exactly how they avoid to see themselves how they truly are.

'Except this isn't a nightmare. It's a mirror. And that's not your nightmare. It's your reflection. This is the moment the program breaks down. When you realize what you are. And the next thought you have sends a bolt of ice down your spine that will stay with you forever'

Dian Wei is an idealized loyal vassal, but what makes him compelling is how his presence forces Lu Bu and Yun to look at themselves in the mirror and realize how one's philosophy has a fatal flaw and how second has an inferiority complex, not being able to uphold his own standards

Lu Bu is not a god who can toy with the lives of people and shape the world according to his own will and whims - the world's rules do not align with his twisted beliefs, mercenaries cant compete with loyalty and even such corrupted lords such as himself can have loyal vassals