nandi will disallowed ravan to enter kailash and will curse him that lanka will be destryed by a monkey Mahadev who was irked by Ravana, pressed his tiniest toe on Kailash pinning him under the mountain. Ravana who was an ardent devotee of Shiva, plucked his nerves and converted them to strings to compose music and sing songs in his praise for years. Mahadev who was pleased with his devotion, not only set Ravana free but also gifted him the divine moon shaped sword Chandrahas. 😊
mahadev will also warn ravan that if he used the weapon for wrong purpose he'll die before his due time😊