A form assumed by अर्जुन in his previous birth. The following story is told in पद्म पुराण (Chapter 14) about अर्जुन being reborn as such at the meeting of कलि and द्वापर yugas and स्वेदज being born as कर्ण during the same period.

Once during a quarrel between शिव and ब्रह्मा the former nipped off ब्रह्मा 's head. (For details see under Brahmā) . Some drops of sweat appeared on the forehead of the angry ब्रह्मा , and from the sweat which ब्रह्मा wiped with his hand arose a person wearing a thousand shields, bow and quiver. That person was स्वेदज . He asked ब्रह्मा what he should do and the former granted him permission to destroy शिव . He then approached शिव with bow drawn and the frightened शिव ran to विष्णु and sought refuge. स्वेदज followed शिव and when विष्णु , seeing him, raised a loud noise 'Hum'. शिव prostrated at विष्णु 's feet. शिव extended the skull in his hand towards विष्णु requesting something to be given to him. महाविष्णु , who had nothing else to give शिव , put his right hand into the skull as alms, शिव wounded the hand with his शूल (three-pronged weapon) and pure red blood began flowing from the hand into the skull. The blood continued flowing for a thousand years in a length of fifty योजनस् and thickness of ten योजनस् . At the end of the period विष्णु asked whether the skull was not filled yet, and looking into the skull with his three eyes शिव answered that it was full. Then विष्णु stopped the flow of blood, and शिव , in the presence of विष्णु , looked into the blood for a thousand years and stirred it with his hand. The blood gradually turned into a bubble, and a person possessing thousand hands and as glowing as fire appeared in the skull. He had a crown on his head and he held in his hands a bow and quiver. He wore gloves on his hands. And, that was रक्तज , an incarnation of नरर्षि .

Looking at रक्तज , शिव told विष्णु thus: "This master in archery is नर . You spoke नर , and let his name, therefore be नर . Oh नारायण , you both will be called नरनारायणस् . This नर will be of help to you on behalf of the देवस् and also in the sustenance and protection of the world. He will further help you to kill the असुरस् . नर , the great intellectual that he is, will become a मुनि , of surpassing wisdom. ब्रह्मा 's divine fifth head possesses so much of effulgence. नर is created from that effulgence and also from the blood from your hands and my look at it. He will annihilate all enemies in war. He will be a terror to those persons who cannot be conquered by you, इन्द्र and the other देवस् .

While विष्णु stood there amazed रक्तज praised him and शिव with folded hands and asked from the skull what he should do. Then शिव ordered him thus: You kill this asura ( स्वेदज ) created by ब्रह्मा with his own effulgence." And शिव led रक्तज out of the skull by his hands and told him again:--"Look, here lies the terrible person I spoke about made unconscious by the cry of 'Hum' by विष्णु . Awake him immediately." After having said this शिव disappeared. नर , in the presence of नारायण , kicked the unconscious स्वेदज with his left foot, and he came out of his unconscious state.

The fierce fight that ensued between रक्तज and स्वेदज continued for two years. By then स्वेदज had lost everything but one of his shields and रक्तज had only his two arms to fight with. At this stage वासुदेव ( विष्णु ) in great alarm went and asked ब्रह्मा whether रक्तज might not kill स्वेदज . ब्रह्मा answered, 'In the next birth नर may defeat स्वेदज '. Saying 'Right, let that be so', विष्णु returned to the battlefield and withdrew them from fighting with the assurance that they would be given an opportunity to fight again during the period of the कलि and the द्वापर yugas.

Afterwards विष्णु directed आदित्य (Sun) and आखण्डल (Indra) to look after रक्तज and स्वेदज . He told आदित्य further:--"At the end of the द्वापर युग you should see that स्वेदज is reborn, in the interests of the देवस् , as your son. In the यदु dynasty will be born a very powerful fellow called शूर and he will have a very beautiful daughter named पृथा . दुर्वासस् will advise her some mantras as a boon and she will have some sons from the देवस् whom she will invoke with the mantras. With that object in view, while in her periods, she would, at the time of dawn gaze at you with love. Then he ( स्वेदज ) will be born as the son called वसुषेण of कुन्ती , the virgin."

The Sun-God agreed to obey the above instructions of विष्णु and told him further:--"I shall procreate in the virgin a very powerful and valiant son, who will become well-known in the world as कर्ण . He will gift away all wealth to ब्रह्मिन्स् ." After saying this सूर्य disappeared.

After this विष्णु told इन्द्र as follows:--"You should, at the end of the द्वापर युग see that this नर , born from blood, is reborn as an aspect of yours on earth. King पाण्डु will one day go into the forest with his wives, कुन्ती and माद्री , and he will then become the object of an animal's curse. He will therefore, in a spirit of renunciation, go to mount शतशृङ्ग where he would ask कुन्ती to become a mother by another man. Unwilling to do so कुन्ती will desire to have sons by देवस् , and when she prays to you, you should favour her with this नर as son.

देवेन्द्र raised a legal objection to the above injunction of विष्णु as follows:--"You, who incarnated yourself as राम in the twentyseventh युग of the last मन्वन्तर for the purpose of killing रावण , killed my son बालि . Therefore I do not wish to procreate नर as my son." To this objection of इन्द्र विष्णु assured him that as a penalty for the mistake of killing बालि , he would be a companion of नर ( अर्जुन ) who would be born as इन्द्र 's son.

According to the above terms and conditions fighting between रक्तज and स्वेदज ended. In the next birth रक्तज was born as अर्जुन and स्वेदज as कर्ण . महाविष्णु incarnated himself as श्री कृष्ण . The meeting of the three in the battle-field is wellknown.