As per the myths, Sahadeva was a great astrologer and was knowing about the Mahabharat battle beforehand. But he was cursed that if he disclosed the events, his head would be split into pieces. Like his brother, Sahadeva was also an expert swordsman.
During the period of exile, Sahadeva vowed to kill the King of Gandhara- Shakuni, who was responsible for ruining their life. On the second last day of the battle, Sahadeva fulfilled his vow by killing Shakuni.
Being the most intelligent brother among the five Pandavas, Yudhisthir appointed him as his personal advisor after the Kurukshetra war. In fact, even Yudhisthir refers to him as being intelligent than Brihaspati- the divine teacher of the devas. He also conquered southern Bharata before Yudhisthira's Rajasuya sacrifice.
Besides being married to Draupadî, he married a princess of Madra named Vijaya. Sahadeva too breathed his last along with his other brothers on the way to Himalayas.