[There's definitely a sense of magic. But it isn't a singular "spell" -- it's more of a creeping corruption from outside that's left a seed here, and that seed's fed on the already overpowering negative emotions his heart carries. The mud (and that's certainly what it is) is the form that corruption takes, and this version of him is the part it's taken.]

Of course not. This soul is rotten. If you cut "me" out, you'd be left with a shell.

[He laughs again, stands up, and he's suddenly outfitted for battle with sword in hand.]

I keep thinking it'd be better to forget who I was and just give in. The other parts of me are so small... they'll drown in this hate eventually. Right now I can only dream of killing you, but one day there won't be anything between "me" and waking up.