vishnu incarnated as the brahman parashurama in this era because there were too many warlike kshatriyas plaguing the earth, and he therefore had to wipe out most of the world's warriors. however, some of the kshatriyas survived or more were created, and their population grew again. eventually, the avatara of vishnu in parashurama ended, though it is said that he continued to live on as a mighty warrior-hermit. he confronted rama, angrily, years later, before acknowledging the latter's supremacy and retiring. he lived on in the dvapara yuga, having a great duel with bhishma for the sake of amba. however he failed to defeat him and stopped fighting after he was forbidden by the divine sage narada and his ancestors and learning that bhishma had surpassed him in art of warfare. he mentored dronacharya, teacher of both the kauravas and pandavas. parashurama also taught karna how to use the "brahmastra" but when he found out that karna had lied about being a brahmana, he cursed karna that his knowledge of the brahmastra would fail him when he needed it the most. he is said to be still alive today, doing penance on the mahendragiri mountain.