Your Strength score increases by 2 and your Constitution score increases by 1,

Demi-Ghouls reach adulthood in their race's respectable age, but retain that age for their prolonged existence.

Demi-Ghouls vary widely in height and build, from barely 5 feet to well over 8 feet tall. Regardless of your position in that range, your size is Medium.

Your base walking speed is 30 feet.

You can speak, read, and write Common, A language of you bodies (previous race prior to ghoulism), and one extra language of your choices.

You gain the Tough Feat.

You have Natural armor granting you unarmed defense equal to 10 +  Half your level rounded down.

At level 3 you unlock a ghoulish transformation that lasts 1 minute. As a action you can transform temporarily creating natural weapons, turning your nails into claws and your teeth into razor barbed canines (or your races equivalent of it). As a action you can attack with the claws, doing 2d6 + STR/DEX + Proficiency bonus. As a action you can attack bite with your enhanced teeth doing 1d8 + Strength + Proficiency bonus. As a bonus action on a successful bite make the opponent make a constitution saving throw, on a failed save you tear a chunk off them eating it, resolving hunger induced exhaustion by 1 and giving temp hp equal to your Constitution score. Damage die on a ghouls natural weapons increases by a single die for each level of hunger induced exhaustion.

As part of your transformation your ghoulish cells are activated giving temporary regeneration. At the end of your turn you recover hp equal to your Constitution modifier + Your half your level rounded down. To recover hp you must have done damage with a melee weapon attack before the end of your turn, you can accomplish this with your natural weapons.

You can use the transformation once per long rest.

Starting at level 10 your body is finishing its evolution, changing your natural form. These changes are unstable developments caused from age and feedings, its uncontrollable by the ghouls what the changes are but the DM can decide based on character behavior 1 of 3 transfigurations.

True Predator - Your actions as a ghoul reflected the behavior of a rabid creature, violently and aimlessly lashing out. In response your body has evolved to improve upon what you're already good at, hunting! Your natural weapons can now multi-attack, you can claw and bite a creature with a single action. Your damage die for natural attacks now gain stacks of bloodlust that increases the damage dealt by a single die and you can gain up to 5 max stacks.  You gain one stack of bloodlust for every successful hit after another, and you lose all your stacks upon a missed attack. Creatures with this mutation are abominable, their ghoulish features are unmistakable, they truly appear to be a monster. Creatures with these changes cannot maintain a façade, making them the least successful kind of ghoul despite their raw power. Even if they tried to convince others they're not harmful their forms disturbs the living, ghouls with this mutation have a -2 to charisma rolls against living humanoids.

Ghoulish Form - Your actions reflected a honest hunter, doing what must be done to survive and existing to live. Its possible you purposely held back against your natural ghoulish nature, in response your natural ghoulish regeneration now happens occurs whether you're transformed or not making you harder to put down for good. You now Passively recover hp, once per turn you can use a reaction to recover hp equal to Constitution + Half your level. If you are knocked unconscious but not outright killed on your turn, you will immediately stabilize upon a successful death save and can recover 1 hp consciousness after 1 minute. Creatures undergoing this transformation exemplify their ghoulish physique, they grow somewhat lankier, and taller but appear more pale with uncanny features reducing your charisma score by -1.

Unstable Transformation - You've been spurratic, unpredictable, and most likely manipulative of your individuals surrounding you. Each feast furthered your growth, every kill absorbed into your being, and yet you have such a firm control over your own mind. What you do is intentional, and methodical, you are among the most dangerous ghouls to exist and its likely few even know you exist. Your determination and self control over your actions has induced a uncontrollable mutation changing your body with the aspects of a slain foe. The DM can check among the list of creatures the ghoul has slain and adapt that races most useful trait into their body. On top of this despite your bodies changes your willpower and ambitions only grow stronger, you gain a +2 to wisdom for a max total possible number of 22. These creatures are the most successful ghouls alive, most of these ghouls live centuries among humanoids undetected. Their ghoulish appearance is mitigated, they appear the most natural out of all kinds of ghouls but as a result all creatures harmed by their natural weapons only take half damage.