Mona is a Human Female located near the Fort Joy main entrance, to the left of the Shrine of the Seven when entering from the front. Mona is covered in a disease, so interacting with her will cause you to contract disease for a few moments. Mona is also the Necromancy vendor on the island of Fort Joy.
Mona's inventory contains..
Blood Sucker, Decaying Touch, Infect, Mosquito Swarm, Rain of Blood and Shackles of Pain.Curing Mona or her affliction will turn her hostile.