Your ability score dexterity increases by 2 and your constitution increases by 1.

You spit fire at a creature within 10 feet of you. The creature must make a DC 10 + your proficiency + your dex modifier Dexterity saving throw, taking 9 (2d8) fire damage on a failed save, or half as much damage on a successful one. Recharges once per long or short rest. Damage die increases by 1 at 5th, 8th, 11th, 15th and 19th level.

You can breathe in smoke, air, lava, and water, as well as ingest lava and other flammable liquids.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You are proficient with either smith's tools or alchemist's supplies.

You are immune to fire damage.

You have advantage on stealth checks while underground.

As a Firenewt you require heat to stay alive. For every week you do not spend at least 8 total hours in a heated condition (a warm interior near the hearth, a sizzling rock in direct sunlight, directly in a campfire or on a bed of coals, wearing magically heated armor, etc.) you take one point of exhaustion. This exhaustion point doesn't go away until you take a long rest in a heated condition.

You speak, read, and write Common, Draconic, and Ignan.