Shri Vadiraja Yati Virachita Dashavatara Stuti – 9
Most people do not realize the contribution of ParashurAma to the kurukshetra war. He was the guru of Bhishma, Drona and Karna; in turn, Drona was the guru for the Pandavas, Kauravas and quite a few other princes. So, in effect, ParashurAma was the source for all the martial skills and knowhow used in the war.