Dream of the Endless vs Nightmare

considering nightmare captured beyonders

this is actually a close fight

The Beyonders have become a joke. Dreams minion, Vertigo's version of Nightmare, would probably wipe the floor with Marvel's Nightmare. Dream wouldn't lower himself to engage Marvel's Nightmare.

Sounds like jobbing by the Beyonders, besides IIRC they vary a lot, the weaker ones were only Herald level or so.

The Dweller in Darkness would be a better match up as Nightmare is his minion and he also created Marvels version of Despair.