As a small feyfox you are nimble (+2 DEX) , cunning (+1 CHA) and magical (+1 INT) but are relatively weak (-1 STR) due to your small stature

Feyfoxes age slowly, they mature at 100 years old and can live until 500 years old

Feyfoxes normally tend towards neutral alignments but some are known to be more evil than others

Feyfoxes are known to be the same height as gnome on their hind legs, your size is small

Your base walking speed is 25 feet (40 ft on all fours) , you have a climbing speed of 20 feet and as you grow you have a flying speed of 20 feet when you hit 12th level

Your time in the twilit forest of the dark area of the fey wild has allowed you to develope excellant dark vision upto a range of 100 ft

Your reflexes and agility allow you to have a burst of speed. When you move on your turn in combat provided you're on all fours you can double your speed until the end of your turn. You can't use this trait again until you move 0 feet on 2 of your turns so your body can recover

Feyfoxes have the ability to drain the life essence of a target should they choose too

When you make a melee attack you can choose to channel your dark aether through a melee weapon. If you choose to do this the target needs to make a Consitution saving throw. The DC for this saving throw equals 8 + your Constitution modifier + your proficiency bonus. A creature takes 2d6 necrotic damage on a failed save, and no damage on a successful one. The damage increases to 3d6 at 6th level, 4d6 at 11th level, and 5d6 at 16th level.. Then the damage you dealt heals you equal to the necrotic damage

You have proficiency in the perception and survival skills

Your birth in the dark recesses of the fey wild as caused you to develope an immunity to Necrotic damage but a vulnerability to radiant damage

Your fur grants a resistance to cold damage

Your nature of being a fey means you only need to rest 4 hours to get the benefits of a long rest

Your dark birth allows you to cast a few spells using this trait

At 1st level you can cast chill touch at will

At 3rd level you can cast false life as a 2nd level spell twice per a long rest using this trait 

At 5th level you can cast cloud of daggers as a 3rd level spell once per a long rest using this trait

You Unleash the dark energy within you as a reaction to being attacked

When you are attacked by a melee attack you can release the dark energy stored within you as a reaction dealing 4d6 necrotic damage to all within 5 feet of you, 5 times per a long rest

You speak poor common but can read fine, you also speak, read and write sylvan and abyssal flawlessly