His battle with her personally was something else. Fighting against such a foe allowed him to unleash. The Order was not worth his time, but Morgana. She had the capability to withstand the full force of his magic. She was easily able to counteract everything he sent her way. Being able to produce a Patronus, let alone augment it into another spell to counter his fiendfyre, was a surprise. The way she was able to easily manipulate spells, it was like a professional dancer, weaving through the room with grace of a queen. 