Same Art + Same Title = same card. This is true for ALL characters and enhancements. See King of Tyrus (Gold vs. Orange). See also Gibeonite Trickery (brown vs. black).
Same Title + Same Brigade = same card. This is true for enhancements and UNIQUE characters. See Gabriel (Warriors vs Disciples). See also Ointment (Warriors? vs. Deck C?)
Same Generic Title + Different art = different card. This is true for Generic characters only. See Pharisees, Pharisees, Pharisees.
Different art + Different Brigade = different card. This is true for characters and enhancements. See Bow and Arrow (good gold) and Bow and Arrow (gray). See also David (red) and David (green). See also Fortify Site (gray) and Fortify Site (black).