Gifuu Doudou!! Kanetsugu to Keiji(2013)

Gifuu Doudou!! Kanetsugu to Keiji is a historical anime set during Japan's Warring States period. Naoe Kanetsugu, chief retainer to Uesugi Kenshin, harbors a dangerous secret: his lord's illegitimate child. He guards this truth while protecting the boy's life, all while partnering with Maeda Keiji, a legendary warrior infamous for his wild, unpredictable nature. Together, the two men refuse to bow to powerful adversaries, carving their own path through an era of constant conflict. Bound by loyalty and their personal code of honor, Kanetsugu and Keiji fight to uphold justice amid the chaos and bloodshed of feudal Japan's final turbulent years.