Spirit naga

Spirit nagas were the most powerful type of naga. They had a human female head on a snake body and were akin to witches among the naga races. They were even more mysterious and enigmatic than the others of their kind, seeking lost magic to a fanatical extent. They delighted in causing suffering and death with the powers they possessed.

Description
Spirit nagas had serpentine bodies with black scales and red bands. Their humanoid faces were framed with stringy hair. The bite of a spirit naga was deadly, as it contained venom. The eyes of the creature were no better, as their gaze could cause others to fall under the control of the naga. The average spirit naga was 14 feet long and weighed about 300 pounds.

Society
In Chult, spirit nagas often took on the role of chieftain over pterafolk tribes.

Appearances
A spirit naga was seen in the novel Red Magic. Here, she was the personal assistant of the Zulkir of Transmutation Maligor. She was depicted as mostly humanoid with the only distinction being that she had a snake tail instead of legs and a small forked tongue. Except for her natural form, she had the abilities to morph into other shapes. Maligor used that ability to replace the manager of Thay's gold mines, thereby taking control of them. This was all part of a complicated plot with the purpose of getting rid of the zulkir of necromancy, his most powerful adversary. In all of this, she showed great loyalty to him, and an ability to commit to a complicated plot, both of which indicated that she was not chaotic evil. More likely she was of a neutral evil alignment. (It is more plausible that Maligor's servant, Asp, is a Shinomen naga of the asp kind, from the Oriental Adventures (3rd edition). In the book she is referred to as a "Daga".)