Dushai is a gnome from Ulgoth's Beard. If Gorion's Ward talks to her before meeting Mendas, she will simply respond that she is meditating and doesn't want to be disturbed. After talking to Mendas, she will tell you a story of Balduran for 100 gp, but only if you expressed your opinion that "knowledge is a worthy pursuit" when you first spoke with Mendas.

I know something of Balduran's story and will share it with you. I require only a bit of gold for me research expenses.