Who gave Amrit Kund to Ravana?

Who gave Amrit Kund to Ravana? Ravan never had any boon for immortality…. Ravan requested Bhagwan Bramha for making him immortal which Bhagwan Bramha disapproved but granted a boon that he can't be killed by any Deva, Asura, Rakshasha, Pisaacha, except humans. Ravan was a Rakshash, a supernatural creature. He was already above the human league. Ravan's biggest weapon was the dart given by Bramha, which was extremely infallible As per Shiv Purana and Ramcharitmanas, Bhagwan Shiva gave his mighty Chandrahaas. Chandrahaas was invincible weapon that not only gave super strength to the wielder but also gave defensive capabilities like creating a barrier to protect him.