In the Marvel Universe, Nightmare had very little presence as a Dimension Demon, and he was not particularly powerful either, roughly on par with the former Lord of the Dark Dimension, Dormammu.
(Dormammu: This never ends, does it? Death smile, Kunkun enraged.jpg)
Moreover, in the original story, both the Ancient One and Strange had died once because of Nightmare.
The most glorious achievement of Nightmare's life was joining forces with the Lord of Hell, Mephisto, to defeat Eternity. Of course, that was not the current Seventh Eternity.
But in a later major event, Nightmare died at the hands of the Lord of Chaos, and a mighty demon god thus faded away.
This time, Lu Chen wanted to test whether he could kill a Dimension Demon for good.
After all, Dimension Demons had rather unusual traits: they were undying and indestructible, could freely roam the universe's timelines, and could not be killed, only banished.
With that thought, Lu Chen immediately headed for the Dream Dimension.
Within the boundless, endless greater universe, ownerless dimensions floated one after another.
Among them was a dimension resembling a dark cloud, within which Nightmare, Lord of the Dream Dimension, lay asleep.
Buzz!
Space flickered, and Lu Chen arrived outside the Dream Dimension in a single step.
"So this is the Dream Dimension?"
Lu Chen looked at the Dream Dimension.
The Dream Dimension before him resembled an enormous screen in a movie theater, playing all kinds of dreams: sweet dreams, nightmares, and erotic...
Ahem, those who knew, knew.
Moreover, the Dream Dimension differed from other dimensions in one respect.
Dimensions such as the Shadow Dimension, the Hell Dimension, and the Sea of Serpents could not descend upon the real world, much less directly invade the dreams of its living beings.
The Dream Dimension, however, could descend