User blog comment:B214/Volume 1 - 15 Discussion/@comment-174.52.115.52-20150422023344/@comment-24098614-20150422110229

The dream of Issei of becoming a hero to the children of the Undeworld is actually quite noble in a way in fact it is the opposite of what a Devil should dream about if you use the Old ways of thinking about them. This dream of his is actually heroic, and sets him apart from other Devils, and Cao Cao went far beyond what he desired, and he paid the price by  having the Sacred Gear reject his dream talk about ironic in a way.

I remember Cao Cao's speech saying that Humans are far superior to Devils and all other Supernatural creatures, and it took the dreams of one evil to show him how wrong he was.