What is the work?
The Netflix series Jessica Jones which was about former superhero turned private detective Jessica Jones. The series already has one PE villain in the form of Kilgrave. But after his death, you have the baddie in Season 3 dubbed Foolkiller.
Who is he?
Gregory P. Sallinger, otherwise known as Foolkiller, is a serial killer who when he was young, had an older brother whom his father favored over him. Gregory always hated his brother who was a talented hack in his eyes. After his brother's death didn't win him any love from his father, Sallinger murdered a boy after a wrestling match then buried the kid on his parents' ground and tormented them with the photos he took. Eventually, he became fixated on killing those he felt were mediocrities to satiate his own ego. When a man named Erik Gelden tried to extort him, Sallinger decides to make him his next target and follows him to Alias Investigations where he accidentally stabs Jessica Jones before escaping.
After torturing and killing 7 people, Sallinger investigates Jessica Jones and concludes that she was a fraud undeserving of her powers and the title of a "hero." He later kidnaps and began to torture Erik and when Jessica starts to conduct research on him, Sallingr kidnaps Trish's mother Dorothy and tortures and kills her. Upon being defeated, Trish decides that imprisonment wasn't too grievous of a punishment, and takes justice in her own hands. She spirits Sallinger away and repeatedly stomps on his head until it caved in.
He resented his older brother for being the favorite of his father and his father even stabbed him at the funeral dinner ranting that he should've died instead. Regardless of this, his sadistic murders do nothing to excuse him and it shows that he is only committing these murders to make himself seem more important than he was.
Nope. Nada. Zilch.
Again, you cannot compare Foolkiller to the likes of villains like Thanos, Hela, or Ego, because he is an ordinary human without even the resources to back him such as the previous Big Bad Kilgrave who had mind control abilities but was differentiated because he was also a serial rapist on top of that. Foolkiller more than makes up for his lack of resources by being as monstrously reprehensible as he could.