what is the role does Reverend Hale? why is he vital?

Rev. Hale is actually a pretty complex character. He is the best witch hunter in the land (how did he land that job?). Initially he has good intentions. He wants to use his "science" to find the truth in Salem. He is important because he represents a ridiculous institution (church paranoia.....) yet his intentions, in his own way, are not malicious. Rev. Hale begins to change as the play goes on. He struggles with his very identity as he sees the obvious shenanigans of Abigail and her fellow crazy girls. Hale comes to represent a sense of personal illumination when John Proctor is so falsely condemned by the church.