what is the relation between kuber and ravan in mythology
Kubera is described as the uncle of Ravana in the "Mahabharata".
Kubera
The "Mahabharata" regards Vishrava as the brother of Kubera, so Kubera is described as the uncle of Ravana and his siblings.
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Kubera [SEP] Puranic and epic descriptions: Godhood acquired
The "Mahabharata" regards Vishrava as the brother of Kubera, so Kubera is described as the uncle of Ravana and his siblings. It records that when Kubera approached Brahma for the favour of superseding his father Pulastya, Pulastya created Vishrava. To seek the favour of Vishrava, Kubera sent three women to him, by whom Vishrava begot his demon children. Ravana, after acquiring a boon of Brahma, drove Kubera away from Lanka and seized his Pushpaka Vimana, which was returned to Kubera after Ravana's death. Kubera then settled on Gandhamandana mountain, near Mount Kailash – the abode of the god Shiva—in the Himalayas.