When you move on your turn in combat, you can double your speed until the end of the turn. Once you use this trait, you can't use it again until you move 0 feet on one of your turns.

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

Tieflings mature at the same rate as humans but live a few years longer.

Feline fiends are the smaller than humans. 

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 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.

You can speak, read, and write Common, Infernal and one other language of your choice.