Your innate magic comes from the ritual sacrifice and cannibalization of dozens of your fellow men, whether by your direct action or through that of your ancestors. These rituals, taught to the yuan-ti by the serpent gods of old, not only transformed their bodies but distilled the magical essence of the slain and infused it into their blood. This concentrated essence flows through your veins, manifesting as both magical prowess and serpentine traits.

 

Form of the Snake

You gain the ability to polymorph into a snake as an action once per short rest. At 1st level you may transform into a poisonous snake. Starting at 4th level you may also choose to become a constrictor snake or giant poisonous snake. Starting at 8th level you may also choose to become a flying snake or giant constrictor snake. You may revert to your normal form at any time as an action.

When transformed, you take on the size, speed, and available actions of the chosen form, but your other statistics remain unchanged. Any equipment you are wearing or carrying is not transformed. If you die while in snake form, you do not revert to your humanoid form. 

Skin of the Snake

Starting at 6th level, your skin becomes chameleon-like, giving you advantage on Dexterity (Stealth) checks made to hide. Additionally, you may use your bonus action to shed your skin and free yourself from a grapple, shackles, or other restraints. If you spend 1 minute eating your shed skin, you regain hit points equal to half your hit point maximum.

Fear of the Snake

Beginning at 14th level, as an action you may inspire dread in your enemies. You target a creature other than snakes or yuan-ti that you can see within 60 feet. The target must succeed on a Wisdom saving throw against your spell save DC or feel an intense urge to avoid snakes and snakelike creatures (including yourself and other yuan-ti), as if affected by the antipathy effect of an antipathy/sympathy spell. If the saving throw is successful, they are immune to this effect for the next 24 hours. You may only use this ability a number of times equal to your charisma modifier per long rest.

Flesh of the Snake

Beginning at 18th level, you gain total control of your transformations, gaining various abilities depending on the type of transformation. As a bonus action, during your turn you may:

• Transform an arm into up to the upper half of five venomous snakes. This grants the ability Flurry of Bites. Melee Weapon Attack: +9 to hit, one creature. Hit: 22 (5d6 + 5) piercing damage plus 10 (3d6) poison damage.
• Transform your lower torso and legs into the lower half of a large constrictor snake. This grants the ability Constrict. Melee Weapon Attack: +9 to hit, reach 5 ft., one Large or smaller creature. Hit: 13 (2d6 + 6) bludgeoning damage, and the target is grappled (escape DC 15). Until this grapple ends, the target is restrained and takes 13 (2d6 + 6) bludgeoning damage at the start of each of its turns, and the you can not constrict another target.
• Transform an arm into the upper half of a large venomous snake. This grants the ability Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 7 (1d6 + 4) piercing damage plus 10 (3d6) poison damage.
• Transform your head into the head of a giant venomous snake. This grants the ability Bite. Melee Weapon Attack: +10 to hit, one target. Hit: 11 (2d6 + 4) piercing damage plus 28 (8d6) poison damage. While your head is transformed, you are unable to speak or cast spells which require verbal components.
• Revert any or all transformations to their original state, however doing so requires as many uses of Flesh of the Snake as transformations to be reverted.

Any combination of these transformations may be active at the same time, however if both arms are transformed you are unable to cast spells which require somatic components. If two or more transformations are active at the same time, you may take the Multiattack action, attacking with once each with any two transformations.

This feature may only be used a number of times equal to your Charisma modifier per long rest.