Nakula (Sanskrit: नकुल) is a major character in the ancient Indian epic, the Mahabharata. He is the elder twin brother of Sahadeva and the fourth of the five Pandava brothers. According to the epic, he was born to Madri, the second wife of King Pandu of the Kuru dynasty, by the grace of the Ashvins, the twin physician gods.
The epic describes Nakula as the most handsome man of his lineage. He was renowned for his skill in swordsmanship and his expertise in the keeping and training of horses. Along with his four brothers, he was married to Draupadi. He also married Karenumati, a princess of the Chedi Kingdom. Nakula had two sons: Shatanika by Draupadi and Niramitra by Karenumati.
During the Rajasuya sacrifice performed by his eldest brother Yudhishthira, Nakula is said to have undertaken a military campaign in which he subdued the kings of the Sivis, the Rohitakas and other dynasties. After Yudhishthira lost his possessions to his cousin Duryodhana in a game of dice, the Pandavas and Draupadi went into exile for thirteen years. During the final year of incognito exile, Nakula disguised himself as a horse trainer named Granthika and served in the kingdom of Virata.
Nakula fought as a skilled warrior in the Kurukshetra War between the Pandavas and the Kauravas. Towards the close of the epic, during the Pandavas' final journey to the Himalayas in pursuit of heaven, Nakula is described as the third to fall, after Draupadi and Sahadeva, on account of his excessive pride in his own beauty.
Adapted from the English Wikipedia article on Nakula (source).