Kenpuu Denki Berserk, Bastard!!: Ankoku no Hakaishin Recommendations
Both are old animes with lots of violence, action and violence on it. Two masterpieces of the gender and same goes for the manga that you won't stop reading/watching before it's over.
Dark ages in both anime as the main content, supernatural or just physical brutal figths, one that acts like an bastard and another one thats just goe´s berserk overall, NOT for the weakhearted!
Both are gritty, violent, and set in medieval times. Bastard is a comedy though, not Dark like Berserk.
Both Anime are set in Medieval times and have great universes full of demons, fairies, battles, royalty and a powerful protagonist. Berserk is the much better Anime.