Which would be the closest synonym for the word specialist

How does the motif in this passage connect to the central idea? read the excerpt from act 5, scene 1, of julius caesar octavius come come, the cause. if arguing make us sweat the proof of it will turn to redder drops look, i draw a sword against conspirators when think you that the sword goes up again? never, till caesar's three and thirty wounds be well avenged, or till another caesar have added slaughter to the sword of traitors the blood motif suggests that revenge will lead to violence and death the omens motif suggests that octavius will die avenging caesar's death the sword motif suggests that all leaders are eventually assassinated the flattery motif suggests that the conspirators will eventually turn on one another