Naruto, Asuma's Will of Fire Is Too Pure.

"Grandpa the Third Hokage bent down to pick up a fallen kunai, looked at the sky and said: 'Damn Otsutsuki!' He threw the kunai out, and saw a battleship in the sky emitting a dazzling light, and then fell. 'This is the Otsutsuki battleship, it has been hovering over the ninja world, and I have endured it for a long time.' Grandpa the Third Hokage said angrily." "The young Konoha ninjas all applauded, feeling proud that Konoha Village has such a Hokage!" ——The first edition ranked No. 1 On the "Fire Nation Books Bestseller List"! Iruka, the honorary principal of Konoha Ninja School, highly recommends it! The Kingdom of Thunder, the Kingdom of Water, the Kingdom of Wind, and the Kingdom of Earth compete for publication! 100 Short stories about past Hokages, intertwined with fun and philosophy, to help young ninjas walk on the right path of ninja! ——"Sarutobi Asuma tells you how the will of fire was created"