the brahmastra is considered to be a very destructive weapon. the brahmastra never missed its mark and could be used under very specific circumstances against an individual enemy or army to uphold dharma (or the rule of law), as the target would face complete annihilation. it was believed to be obtained by meditating upon lord brahma, or from a guru who knew the invocations. according to mythology, the brahmastra is invoked by a key phrase or invocation that is bestowed upon the user when given this weapon. the user would have to display immense mental concentration.