Right from her first moment on-stage Lady Macbeth dominates the stage - she insults her husband, calls on spirits, and then suggests, plans and ensures the success of the murder. In fact, throughout almost the entire play she dominates those around her. In this respect, she is presented as being the most powerful force on-stage. By the end, however, she discovers that the only person she cannot dominate is herself and her own sense of guilt and eventually she (probably) kills herself. Taken as a whole, she has to be seen as a powerful woman, though Shakespeare invests so little time in the latter part of her character arc that it's impossible not to feel a little like she is quite underdeveloped.