Anyway, this work up is for BX DnD but you could use/modify it for S&W or LL very easily.
Armor Class: Variable
Hit Dice: 2-4*
Attacks: 1 by weapon
Damage: 1d6 or by weapon
No. Appearing: 1-12
Save As: Fighter 2-4
Treasure Type: U
Serpent people are the result of the interbreeding of men with serpents during the dawn of mankind. Forced underground by men and elves thousands of years ago they were brought to near extinction. In the dark they prayed to their serpentine god Shurresh (an aspect of Set) and plotted. In recent years they have come to the surface again taking political control of the city of Hlondeth and exerting an above ground presence in the dinosaur infested jungles of Chult. They are also trying to establish control in the dalelands and in the north surging upward from their vast underdark cities.
Most serpent people appear as humanoids with fine scales as skin, and a snake like cast over their faces. They appear dark brown with a greenish purple tint and their eyes are of rust, yellow, or copper. War bands of serpent people typically wear fine chain armor and wield short curved blades and bows. They have infravision to 90 feet in the dark.
Some bands of serpent people will have either a cleric of Shurresh (1-10th level) or a magic user (1-10th level). Additionally, all serpent people have a 50% chance of having mental abilities. Examples of abilities include a charm like ability to fool humans into believing them to be human (save vs. spell to avoid), or domination/summoning abilities over snakes, or ESP. Serpent people are friendly with other serpent/lizard/draconian monsters such as nagas and kobolds, the second they regard as a servant class.
It is rumored that the serpent people have spies all across Faerun. Men whisper aside fires at night that the serpent people steal babies, that female serpent women lure men down dark holes with enchanting songs, and that they torture and breed captive men in their dark cities producing more abominations. There are also rumors that in these cities there are many other twisted forms of snake/men abonminations. Some that area nearly all snakes or men with snakes for arms, etc... there is no proof if these rumors are true.