Your Strength, Constitution and Intelligence scores each increase by 1.

Age is not a physical concept for the wendigo but rather a mental one - the older they get, the larger and hungrier they become. You cannot die of old age.

Wendigo generally lean towards a chaotic alignment. At a younger age, their morals may outweigh their hunger.

Wendigo stand between 7 and 9 feet tall. Despite this size, they weigh as much as the average human at 140 to 160 pounds. Your size is Medium.

Your base walking speed is 30 feet and your climbing speed is also 30 feet.

A human heart still beats inside your decaying chest. Your type is both undead and monstrosity.

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.

The thrill of the hunt and the smell of their fear are almost as good as the taste of their flesh. When you reach 3rd level, you can cast the blur spell once and need to finish a long rest before you can cast it again. When you reach 5th level, you can also cast the fear spell once and need to finish a long rest before you can cast it again. Intelligence is your spellcasting ability for these spells.

Your claws are natural weapons, which you can use to make unarmed strikes. If you hit with them, you deal slashing damage equal to 1d6 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike. You can also bite which is a natural weapon also, If you hit with them, you deal slashing damage equal to 1d8 + your Strength modifier.

You have advantage on Wisdom (Perception) checks that rely on smell.

You are proficient in the Stealth skill.

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

You have resistance to necrotic, cold and poison but a vulnerability to fire. 

 If the wendigo moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the wendigo can make one bite attack against it as a bonus action.

The wendigo can attempt to hide even when it is only lightly obscured by foliage, heavy rain, falling snow, mist, or other natural phenomena.

The wendigo has advantage on attack rolls against any creature it has surprised.