Night Terrors (In general)
Night Terrors are the byproduct of the spells in the dream world. As Poets goal was to create a utopia in the dream world with no evil, pain,anger, or sorrow. the spells he used that affected the minds as they were entering effectively removed them to leave only happiness and such emotions.
nobody knows how they were created. nobody knows where they are. There is no good or hope within them, only evil and anger. They reflect the emotion of feeling they were created from the most.