You can use your fangs and claws as natural weapons.

You can use your action to go into a bloody feeding frenzy tearing a target to shreds. You target one creature within 15 feet of you that is your size class or lower. You leap towards them and pin them to the ground. They must make a dc 17 dexterity saving throw or be knocked prone. You then use your maw attack 3 times in succession. at the end of their turn, they can make the saving throw again, escaping on a success. You can end the attack with your bonus action. If you reduce a creature to 0 hp with this ability, you are healed by the amount of hp they had before the killing blow.

You have no eyes, but you have perfect smell and hearing. You have blindsight around you for 500 feet. You can instantly detect the presence and location of any creature in that radius if they are bleeding or have blood on them. You have no eyes and have no traditional vision. You are unable to be blinded, as you have no eyes to blind. You also are unaffected by all forms of darkness.

You can cast animal friendship on Demodogs without expending a spellslot. You can have a Demodog familiar. You can cast speak with animals only on Demodogs without expending a spellslot. You have advantage on animal handling checks with Demodogs.

You are vulnerable to fire damage but immune to necrotic damage.

You have advantage on and +1 to intimidation rolls. You are also proficient in intimidation.

Demigorgons reach maturity at 15 years of age and can live for up to 200 years, but rarely do so.

Your strength and constitution increase by 2 but your charisma decreases by 1. 

Demigorgons really don't care for the world. They are ambivalent towards the fate of the world. They tend to just want food. They can be good or evil, but they are most often neutral. They also tend to be chaotic due to their loner life style.

Demigorgons are about the size of an average human. They weigh much more though. your size class is medium.

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