A person. A vampire! Angelus: And every creature living on this planet will go to Hell. Cut back to the class. Drusilla: Spike? Giles: Acathla. She punches Kendra and sends her spinning to the floor. That's it. The demon wakes up, and wackiness ensues. Your watcher informed you (imitating her accent) dat a very dark power is about to rise in Sunnydale.
Plan: A: Kendra's Watcher; Q: Who sends Kendra back to Sunnydale? A: a dark power; Q: What is rising? A: Acathla; Q: What is the name of the petrified demon that Angelus, Spike, and Drusilla have found? A: a ritual; Q: What will allow Acathla to wake up and suck every living thing into hell? Summary: Kendra's Watcher sends her back to Sunnydale because a dark power is rising: Angelus, Spike, and Drusilla have found a petrified demon called Acathla and plans to perform a ritual that will allow Acathla to wake up and suck every living thing on the planet into hell.