what is this former one worshipped for?
He is worshipped as the god of wealth.
Kubera
While Kubera still enjoys prayers as the god of wealth, his role is largely taken by the god of wisdom, fortune and obstacle-removal, Ganesha, with whom he is generally associated.
what is the relation between kuber and ravan in mythology Kubera is described as the uncle of Ravana in the "Mahabharata".
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Kubera [SEP] Worship
As the treasurer of the riches of the world, Kubera is prescribed to be worshipped. Kubera also credited money to the god Venkateshwara (a form of the god Vishnu) for his marriage with Padmavati. In remembrance of this, the reason devotees go to Tirupati to donate money in Venkateshwara's "Hundi" ("Donation pot"), is so that he can pay it back to Kubera. While Kubera still enjoys prayers as the god of wealth, his role is largely taken by the god of wisdom, fortune and obstacle-removal, Ganesha, with whom he is generally associated.