Valli

 Bali killed Dundubhi. Sage Matang had his hermitage at Rishiyamooka Mountain. When the stream of blood fell on his hermitage which resulted from killing of Dundabhi, he wondered about thereason. Suddenly a Yaksha came and revealed the secret behind the stream of blood. Indignant, sage Matang cursed Baali that he would die if he ever ventured on Rishiyamooka Mountain. That is the reason Bali could not visit Rishiyamooka mountain.

Brahma had given a boon to Bali which made him virtually impossible to defeat and kill. Whenever facing an enemy in a combat, Bali would get half of the strength of his opponent. He was killed when he was involved in a fight with his brother, Sugriva. (This episode is detailed in Kishkindha kand – The Ramayana)

The might of Bali was such that he defeated and moved around while holding Ravana under his armpit. Ravana, the demon king of lanka and the main antagonist of the Ramayana, was a mighty ruler, but even he was helpless before Bali. So Ravana was weak before monkey ( Bali) and Rama (human).

Once, Bali chased a demon Mayavi after killing his brother Dundabhi. Mayavi entered into a cave where Bali followed him. Bali too followed him into the cave. But before entering he cave, he instructed Sugriva to wait outside for a fortnight. He also said that if he did not come out of the cave after fifteen days, Sugriva would understand that Bali had been killed.

After a month, He saw blood coming out of the cave and assumed that Bali was dead. Sugriva returned to the kingdom as  a king. But Bali was alive. When he came back and saw Sugriva running the kingdom of Pampapuri,he became furious. He drove Sugriva out and enslaved his wife as well.  Sugriva was hiding in Rishiyamooka mountain, because of curse of Sage Matang, this place was safe.