The distinction of being the world’s most violent playwright goes to Shakespeare. His plays are full of wars, massacres, rapes, assassinations, bloody combat, and suicides.
I don’t know of any culture, other than the British (Western) culture, that has a major playwright as violent as Shakespeare. Perhaps the violence we find in Shakespeare is a reflection of the Western method of fighting political battles, in Europe and elsewhere in the globe, with great ruthlessness and ferocity. Europe has become relatively peaceful after 1945 (after the Second World War), before that the Europeans were among the most efficient killers on earth. In his plays, Shakespeare is dwelling on the warlike character of the Europeans of his time.
Tolstoy used to say that at bedtime he always locked his bookshelf because he wanted to ensure that the murderers of Shakespeare would not come out and kill his family.