Anime villains aren’t known for having moral compasses. They will murder, steal, and lie to achieve their goals. However, just like normal people, villains aren’t completely black and white. A villain may be willing to do a lot of terrible things, but that doesn’t mean that every terrible act is fair game.Loyalty and honor can be just as important to the villains as to the heroes. There are even villains who detest violence. The fact that so many villains have positive personality traits is probably why so many heroes try to save the villains instead of killing them.
Ulquiorra is the most loved member of the Espada from Bleach because he has such a dynamic personality. He is entirely loyal to Aizen and isn’t afraid to threaten Orihime’s friends, but committing crimes against her is a step too far.
When Nnoitra confronts Ulquiorra and asks if he plans to punish Orihime, which many viewers read as an innuendo for sexual assault, Ulquiorra is repulsed by the idea and even calls the suggestion vulgar. Orihime may be Aizen’s prisoner, but Ulquiorra is a complete gentleman when it comes to her care, which is what makes their relationship so interesting.