You have resistance to fire damage.

You know the thaumaturgy cantrip. When you reach 3rd level, you can cast the hellish rebuke spell as a 2nd-level spell once with this trait and regain the ability to do so when you finish a long rest. When you reach 5th level, you can cast the darkness spell once with this trait and regain the ability to do so when you finish a long rest. Charisma is your spellcasting ability for these spells.

Your Strength score increases by 2, your Constitution score increases by 1, your Intelligence score increases by 1, and your Charisma score increases by 2.

Goliaths have lifespans comparable to humans. They enter adulthood in their late teens and usually live less than a century.

Goliath Teiflings are between 7 and 8 feet tall and weigh between 200 and 340 pounds. Your size is Medium.

Your base walking speed is 30 feet.

Thanks to your infernal heritage, you have superior vision in dark and dim conditions. 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 have proficiency in the Athletics skill.

You can focus yourself to occasionally shrug off injury. When you take damage, you can use your reaction to roll a d12. Add your Constitution modifier to the number rolled, and reduce the damage by that total. After you use this trait, you can’t use it again until you finish a short or long rest.

You count as one size larger when determining your carrying capacity and the weight you can push, drag, or lift.

You’re acclimated to high altitude, including elevations above 20,000 feet. You’re also naturally adapted to cold climates, as described in chapter 5 of the Dungeon Master’s Guide.

You can speak, read, and write Common, Giant, and Infernal.