Speed burst: By lowering their body to the ground and propelling themselves with their arms, Naga can move more quickly for a time. As a bonus action on their turn, if they have both hands free, they can increase their walking speed by 5 feet until the end of their turn.

Natural weapon: Naga's fanged maw is a natural weapon, which they can use to make unarmed strikes. If they hit with their bite, they deal piercing damage equal to 1d4 + Strength modifier, and their target must make a Constitution saving throw (DC 8 + proficiency bonus + Constitution modifier). On a failed save, the target takes 1d4 poison damage.

Poison immunity: Naga are immune to poison damage and can’t be poisoned.

Poison affinity: Naga gain proficiency with the poisoner’s kit.

Infraheat vision: Viperkin can detect warm-blooded creatures within 30 feet, even through light cover. This does not allow them to see through walls but helps detect invisible or hidden enemies.

Venomous precision: When Viperkin hit with their Bite attack, the target has disadvantage on the Constitution save.

Venomous swiftness: Adder venom acts quickly and their strikes are lightning-fast. When they use their Bite Attack, the poison damage increases to 1d6. Once per turn when they take the Attack action, they can make an additional bite attack as a bonus action. They can Dash or Disengage as a bonus action a number of times per long rest equal to their Constitution modifier (minimum 1).