Regan, the less evil second half to Goneril, is a master manipulator and deceiver in William Shakespeare's King Lear. She sycophantly praises her father in order to gain a third of his kingdom, willingly follows Goneril's lead to oust Lear.
Regan's darkest moments in the play occur in the torture scene of poor Gloucester that occurs in Act 3, scene 7. When Cornwall tortures Gloucester pulling out his eye and stomping on it, Regan bids him to pluck out his other eye.
Then when one of Gloucester's loyal servants begs them to stop the torture and proceeds to fight Cornwall, Regan pulls a sword from another servant and kills him.
Regan is not to be trifled with; her vicious nature is such that even in the end when she is poisoned by Goneril, the audience cannot feel sorry for her.