I'm only going to talk about four of them because we all knw that Chucky was a human who turned into a killer doll so technically a "monster" and Leatherface while a living human beaing was a monster due to his practice of eating people and the fact that he wore his victims skin, Monster through and through.
I feel differently about the details of this story, they say that Jason drown in 1957 but then watched his mother being beheaded on the lake shore ? I think Jason faked his drowning to save his mother from having to care for him and worry about him any longer, this explains why they never fund a body in the lake, right ? So during his initial killing spree at Cam Blood in Friday The 13th part 2 he's a flesh and blood human as well as in part three finally being "killed" in part four "The Final Chapter" (Yeah right) Jason isn't really in part 5 The New Beginning . (great title if you think about the content of the film)
VERDICT : Jason started out Human became a (Zombie) Monster ...
Fred had a deep dark secret that he called his "special work" now in this special work Fred would kidnap, torture and kill young children in Springwood.
Poor Loretta found out about Fred's special work and after swearing she wouldn't tell Fred gave her a really tight double neck squeeze, Poor Kathlyn promised not to tell and she was taken away after Fred was nearly caught for his crimes.
The judge forgot to sign a search warrant in the right place and Fred Krueger was released to contine his special work, what he did count on was the need for justice by the parents of the kids he murdered. they tracked Fred to his boiler room and torched him alive.. End of story, right ?
Becoming known now as Freddy Krueger (the added letters to his name are terrorizing aren't they) Frwddy would set out to slaughter every single kid of the parents that torched him in the one place they were helpless in their dreams !!
VERDICT : Once again a Human (Monster) to start turned into a Monster !
15 years later after a lengthy vacation at Smithsgrove Sanitarium Michael escapes (wish they would've shown this in the classic 1978 film) he goes on a murder spree trying to get to his sister Laura Myers now known as Laurie Strode.
Michaelhas a very long, twisting and honestly confusing history and I won't write it all out so much as I will say that due to the "Mark of Thorn" Michael can only stop killing once his entire bloodline is dead. so Michael can't be killed.
VERDICT : Michael is PURE EVIL ! A (Human) Monster from birth .
This is a MAJOR reason I LOVE the scream series because the killer could be ANYONE :)
VERDICT : Several Bad Ass Human Beings !
STAY HUMBLE, STAY HUNGRY MY FRIENDS :)