Nalakubera had a god, Kubera (god of wealth), as his father and his grandson was Visiravas—in his dark, or demonic, lineage. In a lineage that seemed to recognize more of Kubera’s divinity, Nalakubera’s grandfather (prajapati) was Pulastya (a progenitor).
The demon Ravana was Nalakubera’s uncle. Ravana, the constant womanizer, raped Rambha, to whom Nalakubera was engaged. Rambha pleaded with Ravana that he was an uncle to her and should not do such an evil thing. But Ravana did anyway. Nalakubera was enraged and cursed Ravana: that his head would be split into pieces if he ever touched a woman again without her consent. This was the reason that Ravana could not touch Sita when he abducted her to get even with Rama.
Manigriva was the brother of Nalakubera. One day the two brothers were playing with celestial damsels (apsaras) in a pond, when the cranky old sage Narada came by. When the damsels saw him, they put on their clothes and paid their respects to him. Unfortunately, Nalakubera and Manigriva could not see Narada, and they continued playing in the buff. Narada cursed them for their indecent behavior: they would become two trees in their next birth. They could be released from the curse by Sri Krishna.