Similar anime?
Are there any other anime series which has a similar theme (supernatural thriller dealing with human emotions, moral conflict and violence) and is as good as "X"?
shareA few come to mind. Try Yu Yu Hakusho. It's a much longer series but one of my all time favs (peep the movies while ur at it). Some ppl might tell u to try Inyuyasha but I'm not fond of it. I would say also try Blood+ and Bleach. Those are some of the three better quality anime IMO and all deal with the supernatural, have great storylines, and a good deal of action.
-If the devil really does interfere in this world we've seen his work