Nada was Dream's real love She was the princess of the tribe that was known as"the First People and she met Dream 10000 years before the events

She became infatuated with Dream when she saw him through the tower's window when she was governing her people. He too became enamored of her.

Nada speaks of Dream as Kai'ckul, which is one of the numerous names Dream adopts as Morpheus, 

The Sandman

and the first portion of Dream and her love story is revealed in the prologue of the Sandman'ssecond volume,

"The Doll's House," which the second part of the Netflix show is based upon.

The Sandman, Who is Nada

There Nada admits her love for Dream however when she realized that he was a participant in The Endless,

a group of immortal creatures who can't be destroyed, she returned to the mortal realm because of fear as she realized they couldn't be together.

Dream however, comes across Nada on Earth and proposes for her to become the Queen of Dream. He then invites her to become the queen of Dream realm.

He persuades her to remain with him, but their passion causes the devastation of her family by a meteor, and Nada realizes that they can't remain together.