Complex sentence: She is a committed, rule-abiding young woman who does everything authority figures tell her to do, and is therefore fatally vulnerable to being hypnotized by Drusilla (Juliet Landau), an insane vampire with extraordinary mental abilities who kills Kendra easily.
Split into simpler sentences: She is a committed, rule-abiding young woman who does everything authority figures tell her to do. Thus, she is fatally vulnerable to being hypnotized by Drusilla (Juliet Landau), an insane vampire with extraordinary mental abilities, who kills Kendra easily.