Sentence:  The slasher narrative is as simple as a knife in the head: Some tragic event creates a killer who then seeks <WSD>bloodthirsty</WSD> revenge for that primal trauma, and audiences hoot and cringe in equal measure as characters lose their lives one by one, often in unexpected or inventive ways, until a resourceful “Final Girl” manages to defeat the monster. 
Meaning of the word marked with <WSD> tags:  Thirsty for blood: inexorably violent or eager for bloodshed; murderous.