Ravana is a legendary, demonic king of Sri Lanka, said to have ruled the island 6,000 years ago.
One of the children of the sage Vishrava, Ravana performed an intense penance to Brahma, lasting several years. During his penance, Ravana chopped off his head ten times as a sacrifice to appease him. Each time he sliced his head off a new head arose, thus enabling him to continue his penance. At last, Brahma, pleased with his austerity, appeared after his tenth decapitation and offered him a boon. Ravana asked for immortality, which Brahma refused to give; in place of this, he asked for absolute invulnerability from and supremacy over gods, heavenly spirits, other rakshasas, serpents, and wild beasts. Contemptuous of mortal men, he did not ask for protection from these. Brahma granted him these boons.
Pleased with his resilience and devotion, Shiva gave to him the divine sword Chandrahas. It was during this incident that he acquired the name 'Ravana', meaning "He Of the terrifying roar", given to him by Shiva – the earth is said to have quaked at Ravana's cry of pain when the mountain was pinned on him. Ravana in turn became a lifelong devotee of Shiva and is said to have composed the hymn known as Shiva Tandava Stotra. Shiva had given his sword Chandrahasa with a warning that if it was used for unjust causes, it would return to the three-eyed one and Ravana's days would be numbered.
His abilities now truly awe-inspiring, Ravana proceeded on a series of campaigns, conquering humans, celestials and other demons. Conquering the netherworld completely, he left his brother Ahiravana as king. He became supreme overlord of all Asuras in the three worlds, making an alliance with the Nivatakavachas and Kalakeyas, two clans he was unable to subdue. Conquering several kingdoms of the human world, he performed the suitable sacrifices and was crowned Emperor. Ravana defeated Indra and the gods, Surya, Varuna and Yama.
Kubera at one point chastised Ravana for his cruelty and greed, greatly angering him. Proceeding to the heavens, Ravana fought and defeated the devas, singling out his brother for particular humiliation. By force he gained command over the devas, celestials, and the serpent races. At the time of the Ramayana, set several years later, Ravana is shown as dominating all human and divine races – so much so that he can command the sun's rising and setting.
However, his downfall begins as he steals Sita, the wife of the hero, Rama, the God Vishnu in human form. Rama travels to Sri Lanka and defeats Ravana's army, then kills the demon king.
He's an arrogant lecher who responds to most requests with either sarcasm or casual insubordinance. However he's very devoted religiously and was a legitimately good king to his people. Passionate, capable and very ruthless. He is a sarcastic devotee to his Master, whomever they may be. He only serves them as the notion amuses him. For the time being.