Just thinking about the Cobra gloating 'I enjoyed that,' when asked about ruining a young man's life, and about Marius later finding out that said man had been selling people into slavery, and that the Cobra was also grieving a loss that wouldn't have meant anything to Marius at the time.
And then in AHC, when Marius is telling the Cobra about the worst thing he ever did, about destroying his father's body and spirit as he threw him off the battlements, he says, 'You don't understand. I was laughing.'
It's interesting to think of Eric going from a kid who believes Marius stands for everything good and true, to an adult who has experienced some of the same internal conflicts, including the righteousness you can feel being cruel to someone awful, and how it feels to lose someone. The whole point of having a favourite character who does bad things is to reflect your own darkness; their deeds may go much further than yours but their depths reflect how you felt at the time.
