It's incredibly edgy and filled with trigger-warnings, I will say that much. Yeah, he may think that his existence doesn't mean anything but he still likes himself. Liking himself, being a good person, and thinking what he's doing matters are all three different things that have nothing to do with one another in his opinion.

Nero is a huge proponent of personal responsibility and responsibility. Like, he never acts like he's a victim nor a blind follower. He does exactly what One wants him to do, but he never acts like, "Oh, I just did what you wanted so I have no "part" in what happened." He absolutely is aware of his part in everything and really hates people acting like they had no part in events.

So, yeah, long as Emet-Selch and she take their amount of blame and don't try to shove it off as, "Oh, I had to because I had no choice and no way to not do it yadda-yadda-yadda;" he generally will be cool and willing to listen to any complaint that either one of them has with minimal judgements (smart-ass comments, however, are going to be given).