I assumed he was evil from the beginning... He doesn't communicate. It doesn't make sense that he "stopped the darkness", because it's still here and hasn't been coming close to the city without him 'protecting' it. Made more sense that we stopped the traveller and now the ghosts are spying on the guardians - the only ones that can stop him after regaining consciousness. It would be an easy/lazy plot twist that would trip out some of the simple minded players... Exactly what I'd expect from the writers.