Samurai Spirits, or Samurai Shodown in the west, has received two animation adptations to date. The first was the poorly received Samurai Shodown: The Motion Picturem which took HUGE liberties with the property and ended up receiving a very negative response. The scond anime was released in 1999. Titled Samurai Spirits Asura Zanmaden, the two episodes ova bridges the gap between Samurai shodown 64 and Samurai Shodown 64-2, two games not quite popular either due to the fact they were only available on the ill-fated Hyper Neo Geo arcade board. This second anime did not cater for new fans or those who did not follow the story of the 64 Samurai Spirits, in fact it presumes that the viewers know the charactres and how the the previous game ended.
Samurai Spirits Asura Zanmaden was never licensed outside Japan, and in even inthere it only had one released in laser disc back in 1999. Luckily for us, fans of the Samurai Shodown series made a fan sub which you can watch below. And to help you understand wah the hell is going on, below is a recap of what happened in Samurai Shodown 64 game (from SNK Wiki):
Six months after the defeat of Mizuki, the final boss of Samurai shodown 2, Yuga the Destroyer, another being originating from the Makai realm, moves to conquer the world half a year after Mizuki’s defeat. Twenty years prior to Amakusa’s resurrection, it enters the human realm and steals various babies from mother’s wombs and using its power, bestows superhuman abilities upon them. It silently re-inserts the unborn children, and waits for them to grow into superhuman warriors. Upon their adulthood, it appears before all of them and brainwashed all of them to become its loyal slaves through a magical puppet show. One of its victims is a mysterious woman named Shiki, the perfect female counterpart for Yuga’s vessel. Yuga orders Shiki to find the perfect male counterpart, intending to merge the two for its eventual resurrection. Haohmaru is selected but Yuga underestimates him in their battle. Haohmaru defeats it and frees Shiki from its mind-control.
Now that you have an idea of what happened during Samurai Shodown 65, sit back and enjoy the full two episodes anime Samurai Spirits Asura Zanmaden!