Lord Of Underground

I'll let you know right away that this is the first time I'm taking up writing, also constructive criticism would be appreciated, English is not my native language, also I'm using the help of a translator, and Grammarly, information about mistakes would be welcome. The first 3 chapters will be a prologue about the last moments of an old soul inhabiting a body - Yes, the MC will be a different person, a bit.... scarier Additional tags: GORE, MUCH GORE, EVIL MC Synopsis: A demon born on the lowest floor of hell gathered power for hundreds of thousands of years, eating his sisters, killing his brothers, finally came to the throne, his only descendant, betrayed him, poisoned him, stripping him of most of his power, in his final moments he sent the seed of his soul to a random side of the universe, which sat in a random young man named Derek, the Demon came to life years later and whispered in the back of Derek's ear to create the perfect vessel until finally taking over the body, the Demon wanted revenge on the entire underworld. Also, I don't know how to write the best synopsis, but yes - the person who appears in the first chapters is not the MC, he will be a temporary character during the first 3 chapters - Prologues, from about chapter 4 we will learn the genesis of our MC and finally get to the main story