Jhesiyra Kestellharp

Jhesiyra Kestellharp was one of Halaster's seven apprentices who accompanied him to Undermountain. She is noted as the primary source of information on Halaster as she was the only one of the seven ever recorded leaving those halls.

Biography
She traveled to Myth Drannor where she studied magic among the elves before she became Magister in 658 DR after the electrocution of Dathchaunt Sandrach. She experimented with the creation of sentient spells, basing her research on the elven theory of arcanaweaves, re-invigorating their research with her human passion and binding herself into the magic. In 667 DR, in an incident neither Azuth nor Mystra were willing to speak of, the mantle of Magister passed from Jhesiyra to Nerren Prentiyuel - Jhesiyra apparently having transformed herself into a particularly powerful living spell.

Jhesiyra disappeared, seemingly nowhere to be found anywhere in Faerûn, though some theorized that she had been abducted by her former master, Halaster. This theory was true, but concerns about her death were unfounded. Halaster had abducted and imprisoned Jhesiyra to create living spells for him.

She came to rule over the other living spells that she'd created, escaping her prison and taking over Undermountain's Citadel of the Bloody Hand, destroying the waterdhavian Guard garrison stationed there. Driven half mad by her transformation and centuries of imprisonment, she lived in constant fear of Halaster exacting his retribution for her escape, even after his death in 1375 DR.