Your creature type is humanoid

Your creature size is Medium (about 5-6 feet tall)

You have a base speed of 30 Feet

Your serpent anatomy gives you Blindsight with a range of 5 Feet

Your lineage stems from one of three types of great serpents which bestowed their venom to your ancestors, Choose a heritage from the list below

Fangborn of Jade:

Fangborn of Jade have light to dark green scales all around their body with skin ranging from pale white to pink. Much like their Serpent Goddess, these Fangborn’s bodies are often lean and athletic, allowing for easy maneuverability around terrain such as trees in the woods they often occupy.

Fangborn of Topaz:

Fangborn of Topaz are one with the earth, possessing brown to greyish scale and a natural skin color of tan to golden brown. Much like their Serpent God these Fangborn’s bodies are often broad and built, allowing for big feats of strength and the natural ability to shape the mountainous rocks around where they live into useful structures and tools without any additional help.

Fangborn of Obsidian:

Fangborn of Obsidian are less often seen in nature, preferring to stay under the shroud of the dark caves they make their living in. On the rare occasion that an individual of this type of Fangborn ventures and inhabits the outside world, one would often see dark purple to pitch black patches of scales all round their bodies with often sickly-looking pale skin. They say when an Obsidian Fangborn sneaks up upon its prey at night, their target’s most assuredly would not make it to sunrise.

When you take the Attack action on your turn, you can replace one of your attacks to make a melee attack roll with a bite of your jaw, if you do, you can use your Dexterity modifier instead of Strength modifier for the attack. On a hit, the creature takes 1d6 + your Dexterity modifier of Piercing damage. 

When you reach character level 3, you can transform your legs into a serpent’s tail as a Bonus Action. The transformation last for 1 minute or until you end it (no action required). During that time, your walking speed increases by 5 feet and you have a climb speed equal to your walking speed. In addition, you also gain the following benefits based on your Fangborn Heritage while you're transformed.

Venom’s bite (Fangborn of Jade).

When you hit a creature with your bite attack, you can choose to attempt to poison your enemy. The target must succeed on a con saving throw (DC 8 plus your Dex modifier and Proficiency Bonus) or have the Poisoned condition until the end of your next turn. You can use this trait a number of times equal to your Proficiency Bonus per long rest

Earth’s Coil (Fangborn of Topaz).

When you hit a creature with your bite attack, you can choose to attempt to grapple your enemy with your tail. The target must succeed on a str saving throw (DC 8 plus your Str modifier and Proficiency Bonus) or have the Grappled condition until the end of your next turn. You can use this trait a number of times equal to your Proficiency Bonus per long rest

Shadow’s Veil (Fangborn of Obsidian).

When you hit a creature with your bite attack, you can choose to attempt to frighten your enemy with your stare. The target must succeed on a wisdom saving throw (DC 8 plus your Charm modifier and Proficiency Bonus) or have the Grappled condition until the end of your next turn. You can use this trait a number of times equal to your Proficiency Bonus per long rest

When you reach character level 5, you are able to gain the protection of your Serpent deity for a brief moment, you gain the following benefits based on your Fangborn Heritage:

Jade’s Resilience (Fangborn of Jade). Once per turn, whenever you have the Poisoned condition, you can choose to remove it as a bonus action. If you do, gain a number of temporary hit points equal to your proficiency bonus.

Once you use this trait, you can’t use it again until you finish a Long Rest.

Topaz’s Might (Fangborn of Topaz).  Once per turn, whenever you have the Grappled or Restrained condition, you can choose to remove it as a bonus action. If you do, gain a number of temporary hit points equal to your proficiency bonus.

Once you use this trait, you can’t use it again until you finish a Long Rest.

Obsidian’s Cunning (Fangborn of Obsidian).

Once per turn, whenever you have the Charmed condition, you can choose to remove it as a bonus action. If you do so, gain a number of temporary hit points equal to your proficiency bonus.

Once you use this trait, you can’t use it again until you finish a Long Rest.