The 6th season of Huyao Xiao Hongniang

Kenshiro is the heir of the legendary martial arts known as Hokuto Shinken, which can kill a man with a single blow, by striking the pressure points in the enemy's body. Hokuto Shinken can be passed only to one successor at a time. When he was chosen as the successor, he parted ways with his brothers, Toki and Raoh. The former decided to use what he knew of the art to cure people... while the latter has chosen to use his supreme strength to install peace in the world by power. Kenshiro is accompanied by Lynn and Bart, and the movie's story begins when an overlord starts kidnapping children to use them as slaves for building his own pyramid... (Source: AniDB)

Last of the Shin Kyuuseishu Densetsu pentalogy. A prequel set between Kenshiro's defeat at the hands of Shin and the beginning of the manga. (Source: Wikipedia)

For the invincible and basically happy punk lads Hiroshi and Toru, what they care about every day is to get a lot of attention from girls and to win the fights against the lads from other schools. Whenever provoked, they just go out fighting and settle the situation no matter what it costs.