I'm currently watching Berserk. It's a fantastic show. It reminds of a cross between D&D and Dark Souls. The characters are all mercenaries in a world with hidden magic and monsters. I'm still only halfway through, but I suspect magic and monsters become much more prevalent as the series goes on.
The series starts with Guts fighting a monster lord, and then goes back in time till when he was a younger mercenary. Much of the series is taking place in the past.
Lots of nasty politics, big battles, and bloodshed. Another neat thing is that the armor appears to be a mix of medieval for leaders and English Civil War for the more common troops. I like it.
I haven't finished the show or read the manga, so no spoilers, please. Just wanted to say this anime is perfect for D&D fans.