Nightmare (Marvel)

Nightmare is a recurring villain in Marvel comics, frequently antagonising Doctor Strange - Nightmare also acts as the personification of nightmares and is often referred to as a demon prince of the dreamscape.

History
Nightmare controlled one of the Splinter Realms known as the Nightmare Realm and the Dream Dimension. His interference with mortals often caused him to come into conflict with Doctor Strange.

A man named Havelock revealed that twelve years before he (Havelock) first encountered Doctor Strange he had washed up on one of the Sunda islands. There he encountered an old woman. During the night, the old woman had to fight off Nightmare, overlord of the Dream dimension.

Approximately 800 years ago, Nightmare raped the demoness Zilla Char, producing a daughter, Dreamqueen. Then, 350 years ago, Nightmare meddled with the Dreamqueen's schemes involving Native Americans.

Nightmare was fiercely protective of his realm, having warded off attacks from his daughter and other demons seeking to depose him.

Nightmare acted as a servant of Shuma-Gorath.

Nightmare expressed that he had grown bored and run out of ideas to torment dreamers with. He visited the realms of mortals to seek 'motivation.' He took control of a nightclub, renaming it 'Club Fear.' Patrons were briefly exposed to their nightmares. There he posed as owner Edvard Haberdash, becoming romantically involved with a horror movie actress.

Nightmare once tormented the Hulk and Betty Ross Banner. Along the way he also found his renegade daughter, Daydream.

Nightmare once attacked Magik (Jimaine Szardos) and Nightcrawler, while under Hive's control, attempting to claim the Soulsword.

Powers and Abilities
Nightmare is able to capture a sleeping person's astral form and bring it to his realm. There they are tormented in various ways as he chooses. Nightmare can summon a number of lower beings in his realm such as succubi to do his bidding. Nightmare can summon his mount, Dreamstalker when needed. Under normal conditions, Nightmare cannot affect an individual who is awake. However, his images and other creations can continue to haunt a person in their waking hours. Nightmare has been shown capable of simultaneously subduing two Earth demigods, an Eternal, an Elder God, and a genius-level human teenager with ease through magic while assessing their worst fears from the darkest crevices of their minds, though is actually capable of sustaining reasonable physical harm with one strike from Hercules. His existence and vast knowledge is known to the Council of Godheads. As long as there are beings that dream, Nightmare will exist. While he has been defeated, he can never truly be destroyed.