The Serpent

There's an awful lot of snakes out there. It's your lucky day, one of them has chosen to grant you special powers.

Possible patrons for this include: Dendar, Jormungandr, any kind of couatl or naga.

Expanded Spell List

1st: Ray of Sickness, Tasha's Caustic Brew
2nd: Acid Arrow, Summon Beast
3rd: Blinding Smite (the damage type is poison), Blink
4th:Vitriolic Sphere, Greater Invisbility
5th: Cloudkill, Dominate Person

Scales of the Serpent

Starting at 1st level, when you aren't wearing armor, your AC equals 14 + your dexterity modifier (maximum 2).

Serpent's Fang

Starting at 1st level, you gain an unarmed attack that uses your dexterity and deals 1d4 piercing or slashing damage on a hit, you are proficient in it.

Additionaly you gain the ability to infuse either a natural weapon or a weapon you are holding with venom using a bonus action.

You can do this an amount equal to your proficiency bonus per short rest.

The poison deals 2d4 damage, which can be halfed with a constitution saving throw against your spell save DC.

The damage increased by another 2d4 at 5th, 11th and 17th level.

 

Potent Venom

Starting at 6th level, once per turn when you deal acid or poison damage, you can add your charisma modifier to the damage dealt.

Additionaly you can ignore resistance to those damage types.

Starting at level 14, you can also ignore immunity.

Serpent's Blood

You gain resistance to poison and acid damage.

Toxic Blood

Starting at 14th level, whenever you are dealt damage, you can use your reaction to force each creature within 10 feet of you to make a Dexterity saving throw against your spell save DC.

On a failed save a creature takes 2d8 acid as well as 2d8 poison damage and is blinded until the end of your next turn, a sucessful save halves the damage and doesnt blind the target.