( The 'sh' in this name is pronounced like 'sh' in 'shy' and 'n' like 'n' in 'morning'. Also, 'ri' is not a consonant soud but it is a special vowel sound with no English equivalent. )
In Mahaabhaaratham, the name Krishna can refer to any one of Krishna, Arjuna,Vyaasa and Droupadi . Don't get confused. Also, a sage of the same is mentioned in Shaanthi parva while listing sages that were present with Bheeshma during his last days.
Krishnaá principal weapons were four - a discus named Sudarshana, a mace named Koumodaki, a bow named Saarnga and a sword named Nandaka, all in fact those of Vishnu himself. His conch was named Paanchajanya. His driver was Daaruka. The steeds yoked to his chariot were named Sugreeva, shybya, Meghapushpa and Valaahaka. The gem he ears was known as Kousthubha. He had eight principal wives - Rukmini, Sathyabhaama, Jaambavathi, Mithravida, Kaalindi, Naagnajithi, Bhadra and Lakshana. some of these were his cousins. Pradyumna, Gada, and Saamba were his principal sons.
Krishna is the king pin in the story of Mahaabhaaratham. He was the seventh incarnation of Lord Vishnu. Of all the incarnations ( prominently ten, though there were many), Raama and Krishna incarnations were considered to be comprehensive in all respects. The difference between these two is that Raama behaved like an ideal human being without going for much of oral teaching while Krshna took the role of a teacher of philosophy of the highest order. Also, Raama appears like a human attaining divinity while Krishna appears as a divine coming to be a human.
Krishna was born to Vasudeva and Devaki. Balarama was his half brother, born to Vasudeva and Rohini. Owing to the feras of his maternal uncle Kamsa that Devaki's eith son would kill him, Kamsa imprisoned Vasudeva and Devaki after their marriage. The eighth son was secretly smuggled out to a small hamlet of cow-keepers whose chief was Nanda, in exchange with the latter's daughter. Balaraama and Rohini were already there with them for safety from Kamsa's attrocities.
Krishna grew up with the cow keepers. Kamsa's search for his slayer and information from Naarada revealed that Krishna was the boy who would kill Kamsa. Kamsa sent Akroora to bring Balaraama and Krishna on the pretext of invitation to his Dhanuryaaga ( a sacrifice) only to kill them. They went to Kamsa's city Madhura. Kamsa's efforts to kill them with his mighty elephant Kuvalayaapeeda or his terrible wrestlers Chaanoora and Mushtika, were foiled and Krishna killed him in the public. He then released the imprisoned king Ugrasena ( Kamsa's step-father ) and his own parents too. By killing Kamsa, Krishna incurred the wrath and hatred of Kamsa's father-in-law, the powerful, mighty and much-dreaded Jaraasandha of Magadha. Jaraasandha's two daughters Asthi and Praasthi were Kamsa's wives. Due to his relation with Kamsa, Jaraasandha attacked Krishna's place Madhura, seventeen times each time with a huge army of twenty three Ashouhinis. Finally. Krishna shifted his people to a sea-bound city Dvaaraka which he got built by Vishvakarma, the architect of the celestials.
As Krishna grew up, he adopted several strategies to defend his clan and attained supremacy over all his rivals. He killed many demons since his childhood and gained fame all over the country. He had eight principal wives Rukmini,Sathya,Jaambavathi,Lakshana,Mithravinda, Naagnajithi,Kaalindi and Neela. His sons were Pradyumna, Saamba etc.
In the Mahaabhaaratham, his role starts from Droupadi's svayamvaram where Arjuna ,in a Braahmana's guise, won her and defeated the team of jealous kings who attacked Drupada for insulting the ruling races by giving his daughter to a Braahmana. He convinced the agitated kings and went to see the Paandavas. From that day, his relation with them became stronger and stronger. He supported them till the end and stood against the kouravas all the while, despite his brother Balaraama's strong affection to Duryodhana.
By relation, Paandavas' mother Kunthi was sister to Krishna's father Vasudeva. Thus Krishna and Paandavas were cousins. He was elder to Arjuna and younger to Bheema. On the other hand, Duryodhana's daughter Lakshana was married by Krishna's son Saamba. Thus Krishna was directly a relative to Duryodhana ,by marriage. Yet, Krishna never stood for the kouravas since they were cruel and wicked to their cousins Paandavas.
Krishna's role in Mahaabhaaratham is pivotal. He liked Arjuna very much. They both helped Agni against Indra, in consuming the Khaandava forest thereby acquiring the Gaandeevam and Discus for them. Krishna gave his sister Subhadra to Arjuna in marriage with a strategem against his brother Balaraama and others. That made their relation still more fonder. He advised the Paandavas to undertake the performance of Raajasooya sacrifice to establish emperrorhood of Yudhishthira. He saved Droupadi from insult of being disrobed in the public court hall by the kouravas. He consoled and encouraged the Paandavas while they were in the forests. After their exile is over, while attending Abhimanyu's marriage function, it was Krishna who first moved the issue of the Paandavas' share of the kingdom and proposed for gathering all the allies for the war. Later, when Duryodhana and Arjuns met him the same day for help in the war, he managed that Arjuna too had a chance to be helped and joined the Paandavas side, though as a non-fighting helper, apparently.
Krishna was the emisaary of the Paandavas sent to the kouravas for settling the issue of their half-share of the kingdom. He tried his best for the truce, though not hiding the readines for a war. The kouravas tried to capture him but he warded off their efforts by displaying his universal manifestation. Before leaving, he met Karna privately and disclosed his birth secret that he was actually Kunthi's son and thus he should come over to his real brothers the Paandavas. Though Karna did not accept his proposal, the disclosure of such a sensitive matter at such a crucial point of time must have had its bearing on him. Krishna was famous for his diplomatical tactics like that.
During the war, Krishna's help to the Paandavas was immense though he did not actually wield the weapon. He advised encouraged and helped them in any ways. In defeating Bheeshma by encouraging Yudhishthira to seek the help of the grandsire himself, in convincingly forcing Yudhishthira to lie about Asvaththaama's death to Drona to kill him, in guarding his side from Asvaththaama's devastating Naaraayana missile ,in provoking Arjuna to kill Karna in a distress with the latter's car-wheel struck in the earth, in reminding Bheema of his vow of breaking Duryodhana's thighs with a mace when the final combat between those two was in progress, in taking the Paandavas away from the camp on the eighteenth night for saving them from Asvaththaama's attack, in saving Bheema - after the war - from their blind Uncle Dhritharaashtra's deadly embrace, every time he proved to be their lead hand. It is impossible to believe that a non-fighting ally could accomplish such a great advantage in war. After the war, he incured the curse of Gaandhaari that his clan too would get destroyed by internal strife.
After the war too, he consoled the dejected Yudhishthira to accept the responsibility of the rulership. He helped him in performing three Ashvamedha sacrifices.
A few years after the sacrifices, Krishna left for his home Dvaaraka. Other facets of his life are clearly described in the Harivamsham ( appendix to the Mahaabhaaratham) and Bhaagavatham ( one of the eighteen Puraanams).
Nearly after thirty six years from the great war, there occured a series of unpleasant incidents among the Yaadavas which portended their destruction. They all killed one another and perished. Krishna sent Daaruka to Arjuna to bring him to Dvaaraka to take care of the women and children. Meanwhile, Krishna prepared himself for renunciation and settled himself in the shade of a tree. A hunter named Jara shot an arrow at his foot thinking that it was a deer. Krishna left this world to reach his abode. Bhaagavatham says that the age of Kali started at the moment of Krishna's leaving this world. He lived on this earth for a little bit over 125 years.
Arjuna reached the city nearly a week after Krishna's death. He wailed and sunk deep in grief. He took away the women, children and Krishna's queens to Indraprastha. Soon after Arjuna's leaving the city, the sea inundated Dvaaraka and immursed it under it forever.
In the way, a band of robbers attacked Arjuna to rob the women and their ornaments. Arjuna could not fight at all. He could not wield his bow, he could not employ his divine asthras either. With great difficulty, he could save only the eight principal wives of Krishna from the attack. Thus Arjuna proved to the world that it was Krishna who made him so famous a warrior. With Krishna gone, Arjuna's everything was gone too!
Krishna's departure so thoroughly disturbed the Paandavas that they spent no time in deciding to leave this world.
Krishna was an ideal example for an undisturbed philosopher, teacher, guide and warrior. His life was multi-faceted. His abilities, wisdom,courage,leadership and dexterity in handling things are to be eulogised by all at all times. This country shows its devotion to him by celebrating his birth day ,Shraavana bright eigth day , as national festival.