Der Kindestod

Der Kindestod is the main antagonist of the Buffy the Vampire Slayer episode of the Killed by Death.

History
Der Kindestod was a cruel demon that killed many children devouring their lives, and the process made her look like they were going to die of fever. However, he targeted children who here already sick and so left little evidence that the death of the children were supernatural. One of his victims Celia who was killed by him, and was the cousin of Buffy Summers who traumatized her. And so, unable to be seen by adults, it could only be seen by sick children or people with high fever. In 1998, Buffy now a Slayer, meets Der Kindestod whem she became ill, where the criature was commiting evil deeds. Buffy then fought the monster and killed him by snapping its neck.

Trivia

 * Both his deformed appearance and the fact that he kills a child can be a tribute to Freddy Krueger the famous nightmare serial killer of the horror movie.