Okay

This part of the plot is applicable to the villain of [Slaying the Demons]. 

The villain, who used to be Keith, has gained the support of the demons and became even more stronger when he received the sympathy of the other players and support of the demons. 

Right after Aiden died, Keith started to conquer the higher floors that has many strong ancient demons. He utilized Alicia's support and powers to assist him breakthrough. 

He even defeated the Ancient demon who owned the demon artifact in his hands. And the curse of the Blood Tower took control of Keith. 

Of course, these scenes and what happened afterward are very vague for Lucien. After all, the protagonist died okay?! The emotional damage of seeing the protagonist die brought him to tears.