THE HAKKENDEN: LEGEND OF THE DOG WARRIORS

"During the blood-soaked feudal wars of Japan, the Awa clan faced certain extinction from a rival clan backed by demonic forces. Their clan's salvation becomes a curse when the family dog brings back the head of the enemy warlord but insists upon marrying the lord's daughter! This unnatural union bears fruit, but they are killed; and their eight unborn pups reincarnate as the eight Dog Warriors - The Hakkenden. The eight reincarnated souls travel their separate paths of violence and retribution, but slowly they come together as a formidable group representing the eight virtues of the bushido to slay the demons and redeem their clan!" (Source: DVD Complete Series Back Cover) — Description from AniList community (anilist.co).