You have insect-like wings sprouting from your back. You have a flying speed of 30 feet while you aren’t wearing heavy armor. 

Your barbed spinal tail is a natural weapon, which you can use to make unarmed strikes. If you hit with it, you deal piercing damage equal to 1d4 + your Dexterity modifier, instead of the bludgeoning damage normal for an unarmed strike

When you take the Sting action on your turn, you can use a Bonus Action to inject a dosage of venom into the targeted creature. The creature must make a Constitution saving throw (DC = 8 + your Constitution modifier + your proficiency bonus). On a failed save, the creature takes an additional 1d4 and is Poisoned for 1 minute, the creature may repeat this save at the end of each of its turns. On a successful save, it takes half as much damage and is not poisoned. This damage increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4).

You can use your Devil's Venom a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

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

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

Tieflings might not have an innate tendency toward evil, but many of them end up there. Evil or not, an independent nature inclines many tieflings toward a chaotic alignment.

Tieflings are about the same size and build as humans. 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 resistance to fire damage.

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