Sidisi

Sidisi is a treacherous naga from Tarkir. She epitomizes the decadent and merciless nature of the Sultai Brood.

Original timeline
As the khan, Sidisi considered herself to be the queen of the Sultai and aimed to gather all the clans under her banner. Her allegiance with the rakshasas provided her with incredible necromantic powers.

Alternate timeline
In the new timeline, however, Sidisi never became Khan and she was reduced to one of Silumgar's undead slaves. However, with her unmatched necromantic powers she was the only thing keeping the rest of the naga in any position of influence. Her ability to threaten, sway, and remove other politicians kept Sidisi as vizier at Silumgar's side, whispering tales to the dragon — some to lull and some to disturb.