In a literal sense, the song seems to be about someone who was betrayed and killed coming back for revenge. In a more-or-less symbolic sense, I think it's about someone being eaten by guilt from betraying somebody who trusted them, and more so the person they betrayed excites the guilt (assuming they're, you know, alive), kind of like the song Laid to Rest by Lamb of God where a murderer is tormented by the guilt of, well, murdering someone.
In a literal sense, the song seems to be about someone who was betrayed and killed coming back for revenge. In a more-or-less symbolic sense, I think it's about someone being eaten by guilt from betraying somebody who trusted them, and more so the person they betrayed excites the guilt (assuming they're, you know, alive), kind of like the song Laid to Rest by Lamb of God where a murderer is tormented by the guilt of, well, murdering someone.