( the D in this name is pronounced like 'th' in 'brother')
Subhadra was Krishna's younger sister.
Arjuna went to Dvaaraka in the guise of a sage during his course of going around the countries as a penance for entering Yudhishtira's house when Droupadi was with the latter.
In Dvaaraka, he was enjoying the hospitality of the Yaadavas. Krishna arranged for the services of Subhadra to Arjuna with a view to help Arjuna marry her. Arjuna disclosed himself to Subhadra at an oppertune moment and made arrangements to take her away with him to his city. Krishna planned for a picnic for all of his relatives, allowing Arjuna freedom to implement his plans. Then, Arjuna took her away defeating the city guards. Though Balaraama and others first became angry with Arjuna for stealing the bride, Krishna convinced them about the good match for Subhadra.
Arjuna and Subhadra got their celebrated son Abhimanyu who grew to be a famous archer under his father's training. He was an excellent fighter. He fought bravely for thirteen days in the war. In the thirteenth day war, he was killed by the kouravas in an unjustified en mass attack.
subhadra did not live with her husband in the forests during their exile. Krishna took her to Dvaaraka alongwith Abhimanyu and the five junior Paandavas.