Serpentine Bloodline

Your innate magic comes from serpentine magic that was mingled with your blood or that of your ancestors. Most often, sorcerers with this origin trace their descent back to a mighty sorcerer of ancient times who made a bargain with a snake or who might even have claimed a snake parent. Some of these bloodlines are well established in the world, but most are obscure. Any given sorcerer could be the first of a new bloodline, as a result of a pact or some other exceptional circumstance.

Serpentine Ancestry

Starting at first level, you have resistance to poison damage, and advantage on saving throws against being poisoned. Additionally, you can speak with snakes, and have advantage on any charisma checks made to interact with them. 

Snake Charmer

Starting at 14th level, when you make an ability check that allows you to add your proficiency bonus in Intimidation, Persuasion, or Deception, you can treat a d20 roll of a 9 or lower as a 10 instead. 

Gorgon's Head

Starting at 6th level, you can use a bonus action on your turn to change your hair into a head full of snakes. This lasts until you are knocked unconscious, or you use a bonus action on your turn to undo the effect. Having so many extra pairs of eyes around has certain advantages. While this ability is active, you can't be surprised, you get +1 bonus to you AC, and you get a bonus to your initiative rolls equal to your charisma modifier.

You can't manifest your snakes while wearing a helmet unless the helmet is made to accommodate them, and clothing not made to accommodate your snakes might be destroyed when you manifest them.

Form of the Alpha Serpent

Starting at 18th level, you can become a true Serpentine Sorcerer. As a bonus action on your turn, you can spend 5 sorcery points to transform into a half serpent. This form lasts for 1 minute, or until you are knocked unconscious. When you use this ability, your legs meld together to form a snakelike tail, and thick layer of scales covers your entire body. While in this form, you gain a number of benefits.

• You are immune to being frightened or charmed.
• If you aren't wearing armor, you get a bonus to your AC equal to your charisma modifier.
• Your walking speed increases by 10ft
• If your Gorgon's Head ability is active, the snakes in your head gain an empowered ability. As an action on your turn, you can have them attack a nearby enemy. Make a melee spell attack roll against an enemy within 10ft of you. On a hit, the target takes 10d4 poison damage. This attack ignores poison resistances. If you use your action on this ability, you can't cast spells that aren't cantrips this turn.

You can't manifest your tail while wearing armor unless the armor is made to accommodate them, and clothing not made to accommodate your tail might be destroyed when you manifest it.