Chitrasena, a minor character in the Hindu epic Mahabharata, was a Gandharva king who taught song and dance to Arjuna. He resided in Indra's palace along with his fellow Gandharvas and Apsaras. He also routed the army of Duryodana and Karna in a minor skirmish that took place before the Kurukshetra War.
As Arjuna's teacher
Chitrasena is introduced in the epic in the Vana Parva, as a teacher of music by Indra. Indra foresaw that Arjuna would have to spend one year at King Virata's palace as a eunuch, during which time he would need the knowledge of music and dance. He wanted Arjuna to be trained by the king of the Gandharvas, Chitrasena. Chitrasena began his classes soon and the two also became good friends.
When Urvashi cursed Arjuna to remain a eunuch for life, it was Chitrasena along with Indra who mediated with her to reduce the tenure of her curse to a single year. Chitrasena was able to achieve this by narrating to her the story of the Pandavas and the bravery of Arjuna.
Skirmish with Kauravas
In another incident in the Mahabharata, Duryodhana, Karna, Shakuni, the 99 brothers of Duryodhana, and their wives, with a medium-sized army, were camping at the Dwaitavana in order to track down the Pandavas and jeer at them during their exile. They reached the forest and were taken in by its splendour. Duryodhana planned to swim in the beautiful lakes of the forest along with his wives. But Chitrasena was already camping there along with his Gandharva family and did not want mortals to invade his territory.
Duryodhana was enraged when Chitrasena's soldiers denied him an entry into the beautiful lakes of the Dwaitavana. He gathered his army and along with Karna and others, launched a savage attack on the Gandharvas. Karna fought with Chitrasena but karna was not there that time. Before Karna had come, Chitrasena made Duryodhana his prisoner.
Some soldiers went to the place where the Pandavas were residing and requested them to free Duryodhana. Yudhisthira ordered his brothers to rescue Duryodhana from the Gandharvas. The 4 Pandavas reluctantly hurried off and fought with Chitrasena's army, with Arjun fighting Chitrasena with celestial weapons. Arjuna requested Chitrasena to release Duryodhana. On his request, Chitrasena released Duryodhana. Arjuna also introduced Chitrasena as his dance teacher to his brothers.
Duryodhana was so embarrassed, by this incident, that he wanted to commit suicide, but was halted by Karna, who had returned after taking the Kaurava women to safety. Karna subsequently swore to kill Arjuna and vowed never to drink wine until he kills him.