( The Y in this name is pronounced like 'y' in 'you'. The D in this name is pronounced like 'th' in 'brother')
Yaadavas means lineage of king Yadu . King Yayaathi had four sons. Yadu, Druhyu,Anu and Pooru. Once Yayaathi was cursed by his father- in-law Shukra, to attain untimely ripe old age, as a punishment for his displeasing Shukra's daughter Devayaani. Yayaathi asked all his sons to exchange their youth with his old age. The three elder brothers refused the request. Only the youngest, Puru accepted. Yayaathi disowned the elder sons and cursed them variously, whereby Yadu and his lineage were ineligible to rule the kingdom.
All the descendents of Yadu were called Yaaadavas. There were various sub sects in them like Bhoja, Vrishni, Saathvatha,Kukuru, Andhaka etc. Krishna belonged to the Vrishni subsect among the Yaadavas. Nowadays, it is a popular belief that the cattle grazing community euphamatically known as Yaadavas are these very Yaadavas of Mahaabhaaratham. Since the Mahaabhaaratham Yaadavas are Kshathriyas, this argument is weak , but popular belief is not bound by truth.
Yaadavas first lived in Madhura under rulership of Ugrasena. But, haraased by repeated (17 times) seizures of mighty Jaraasandha of Magadha empire, Krishna shifted all Yaadavas to Dvaaraka city, edging with the sea in the westernmost area. Yaadavas enjoyed great power and reputation under Krishna's lead. Thirty six years after the war, all the Yaadava warriors fought among themselves and were killed , nearly annihillating the race. The city Dvaaraka was inundated by the sea after Krishna's departure.
Other prominent Yaadava warriors mentioned in the Mahaabhaaratham were,
Krishna's grandson Vajra was made ruler of Indraprastham by the Paandavas before they went on renunciation.
Some other yaadavas mentioned in the epic were : Gada, Saarana, Svaphalka ,Nishatha, Anaadhrishti, kraatha, Babhru etc.
Vasudeva (Father of Balaraama and Krishna. Rohini, Devaki, Bhadra,Madira etc were his wives. Note - One of Krishna's wives was also named Bhadra. )
Uddhava ( Krishna's devotee. Went to retire to forests just before the destruction of the Yaadavas.)
Saathyaki( On the Paandavas side, survived the war, but was killed after thirty six years by Krithavarma's relatives in an internal clash among the yaadavas.),
Krithavarma (On the kouravas side, survived the war but was killed by Saathyaki 36 years later, in an internal strife.),
Chekithaana ( On Paandavas side, killed in the war by Duryodhana),
Akroora ( Krishna's close associate. He went to the forests for penance after the destruction of the yaadavas.),
Saamba ( Krishna's son ),
Balaraama ( Krishna's elder half-brother).
Pradyumna (Krishna's son . He was killed in the destruction of the yaadavas.)
Aniruddha (Pradyumna's son. He too was killed in the destruction.)
Sathraajith (Sathya's father. Killed by his kinsmen for the great gem Shamanthakam which gives lots of gold every day to its possessor.