Asi appears as a proper name as the personification of the first weapon ever created according to Hindu epics. A legend concerning Asi appears in the Shantiparva section of Mahabharata. The common term for sword in Classical Sanskrit is khaḍga and khanda in Hindi. In Rigvedic Sanskrit Asi is still used as a term for a kind of sacrificial dagger or knife.
Out of curiosity Nakula, the fourth son of Pandu and the master of swordsmanship questioned the Kuru Grandsire Bhishma on his arrow death bed as to which was the best weapon in all kinds of fighting. In his own personal views Nakula thought the sword to be the most superior since even on having lost one's bow, horse and the chariot, a skilful swordsman could still defend himself against the mace and spear wielders. Nakula further queried the Grand-sire about the origin and purpose of the Khadga as well as about its first acharya ("teacher, preceptor").
Gladdened by these intelligent queries by Nakula, Bhishma related to him the complete Itihaasa (Sanskrit term for 'History') of the Khadga or "divine sword" starting from its creation down to the present.
The Devas approached Brahma the creator of the universe in ancient time and protested against the unjust rule and evil doings of the demons (Danavas namely Asura's who belonged to an evil human race with giant build). Hearing the protest from the Gods, Brahma collected sacrificial objects and proceeded to perform a grand sacrifice with the foremost of the Rishis and Devas at the side of Himalaya.