The official discussion topic on The Return of Sithis

Hmm... How do I put it? She is mildly psychotic, extremely devious and cunning, narcissistic, arrogant, calculating, and very powerful. She likes poetry, long walks on the beach, mass murder, and genocide. She is prone to random bouts of laughter and anger, but is usually calm and composed, even icy. She is very promiscuous, though she has never kept a lover longer than a week, because she has killed them all. She is ruthless and ambitious, and also fiercely loyal to Sithis and the Brotherhood. She is a particularly young Dark Elf, only a hundred or so, and is rumored to be a direct descendant of Barenziah, though that's more background than personality. She enjoys games of chess, and is often seen playing games with various people in her chamber. She has long believed she was invincible, until losing for the first time to a certain High Elf.