Lots of questions can be spawned from this 'never before read' Mahãbhãrata story, but above is the major one.
Until now my perception was that, Nãrãyana was an equivalent God to Shiva and does not require austerities to get power even while in human form, but this story debunks it.
Preface
After unjust killing of Drona, his son Ashwathama in rage invokes various celestial weapons to destroy Pãndava army. Final is Agneyastra. Though it kills 1 Akshouhini, it couldn't even touch Arjun & Keshava. Frustrated with that he leaves the battlefield and goes to Vyãsa for its complete answer. He learns that, he himself was part form of Rudra who himself given a boon to Nãrãyana (Keshava & hence Arjuna) to have ability to win over him during war.
Laying aside his bow, then, the son of Drona speedily alighted from his car, and saying, 'O fie, fie! Every thing is untrue,' he ran away from the fight. On his way he met Vyasa, ...
The son of Drona with voice choked in grief, and like one exceedingly cheerless, saluted him and said, "O sire, O sire, is this an illusion ... Why, indeed, hath my weapon become fruitless? What breach (has there been in the method of invocation)? Or, is it something abnormal, or, is it a victory over Nature (achieved by the two Krishnas) since they are yet alive?" ...
Vyãsa said, "... He that is called Narayana is older than the oldest ones. For accomplishing some purpose, that creator of the universe took his birth as the son of Dharma. On the mountain of Himavat he underwent the severest ascetic austerities. ... he emaciated himself there for sixty-six thousand years, subsisting all the while upon air alone. Once more undergoing severe austerities of another kind for twice that period, he filled the space between earth and heaven with his energy. When by those austerities, O sire, he became like Brahma he then beheld the Master, Origin, and Guardian of the Universe, the Lord of all the gods, the Supreme Deity, who is exceedingly difficult of being gazed at, who is minuter than the minutest and larger than, the largest, who is called Rudra
{(skipping) desription of Shankar}
Having saluted Rudra, that destroyer of the Asura Andhaka, the lotus eyed Narayana, with emotion filling his heart, began to praise the Three-eyed one
{(skipping) similar words for Rudra resembling the description of Krishna himself from Gita}
I am thy devoted adorer,--be graceful unto me. Do not injure me, by causing evil thoughts to penetrate my heart. ... Adored by me, grant me the boons I desire but which are difficult of acquisition. Do not hide thyself in thy illusion.
Vyasa continued, 'The blue-throated God, of inconceivable soul, that wielder of Pinaka, that divine Lord ever praised by the Rishis, then gave boons unto Vasudeva who deserved them all. The great God said, 'O NarayAna with my grace, amongst men, gods, and Gandharvas, thou shalt be of immeasurable might and soul. Neither gods, nor Asuras, nor great Uragas, nor Pisachas, nor Gandharvas, nor men, nor Rakshasas, nor birds, nor Nagas, nor any creatures in the Universe, shall ever be able to bear thy prowess. No one amongst even the celestials shall be able to vanquish thee in battle. Through my grace, none shall ever be able to cause thee pain by the weapon of thunderbolt or with any object that is wet or dry, or with any mobile or immobile thing. Thou shalt be superior to myself if thou ever goest to battle against me.' Thus were these boons acquired by Sauri in days of yore. Even that God now walketh the earth (as Vasudeva), beguiling the universe by his illusion.* From Narayana's asceticism was born a great Muni of the name of Nara, equal to Narayana himself. Know that Arjuna is none else than that Nara. Those two Rishis, said to be older than the oldest gods, take their births in every Yuga for serving the purposes of the world. Thyself also, O thou of great heart, hast been born as a portion of Rudra ..."
This article suggests that the capabilities of Krishna were due to those austerity worth thousands of years towards Rudra/Shiva.
Questions:
Why in this story, Vishnu is depicted as "that (one of the) God(s)" rather than equivalent to Shiva if not more?
If Vishnu is supreme on his own rights then why is there a need of austerity to get supreme powers (note that this particular wasn't the normal austerity, but rather once and for all)?
