Who is Sienna Brooks from the novel, Inferno?

Sienna Brooks is Zobrist’s lover and main disciple. In order to help the provost determine the location where Zobrist hid his plague, Sienna pretends to be a doctor in the hospital where Langdon wakes after being shot.

Although Sienna was a lover of Zobrist, she did not agree with his method of population control. Even after she and Langdon parted ways when Langdon discovered that Sienna was Zobrist’s lover, she continued to try to stop the disease he had created.