In Hinduism, Sugriva was the younger brother of Vali. He was unjustly thrown out of the kingdom because of a misunderstanding by his elder brother and henceforth they became bitter enemies.
Sugriva was helped by Lord Rama to destroy Vali and he in turn gave the Vanara army to Lord Rama to find Sita and rescue her.
In the Hindu epic Ramayana, Vali was the monkey-King of Kishkindha, a son of Indra and the elder brother of Sugriva.
Vali had been known as a good and pious monkey-king, but had been too arrogant to listen to Sugriva after his brother had accidentally sealed the entrance to a cave in which Vali was fighting a demon.
Sugriva had thought that Vali was dead, and so had ruled in his stead, but though he'd tried to explain the situation to Vali, Vali would not listen, and had him driven out of the kingdom.