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.

Heat seeker: Pit vipers' highly sensitive facial pits let them detect even the smallest variations in heat. They can cast Detect Evil and Good once per short rest, using only their thermal sense (not divinity). They gain blindsight 10 feet against warm-blooded creatures (this increases to 30 feet if the creature is invisible or obscured). They have advantage on Perception checks relying on detecting body heat.