He is definitely sentient.
That raises a question as to the nature of his existence, then; if it were actually possible to forcibly remove wickedness, would wickedness have a will unto itself? It seems...incomplete. Maybe I'm overthinking what the episode was trying to present.
				
  Really cool origin, though - a character in our universe based on an alternate universe character interceding due to temporal deviation. But Sela became a considerable figure... only to be scripted worse than Elmer Fudd or Daffy Duck.