‘That is not known. He comes only when needed and only I can summon him,’ Ashwatthama replied with a hint of pride. ‘The celestial astras are usually evoked using arrows, although they can potentially be evoked by any weapon or anything else. I invoked the Brahmashirsha astra using a blade of grass as my weapon. Indra’s son, Arjuna, was capable of shooting all his celestial weapons with the power of his mind alone. He didn’t need any physical vessel for the astra to manifest in.’
