Legends of the Dark King (or more literally translated, Conqueror of the Heavens: Fist of the North Star Raoh Gaiden) is a prequel to Fist of the North Star focused primarily on Raoh building his empire. You could, in theory, watch this short series before you tackle the original hundred episode long series but the story would probably make even less sense; it's just really helpful to know who the characters are. The plot isn't terrible but it is very different from what is normal with Fist of the North Star. While most Fist of the North Star anime is focused on one guy punchinga bunch of other guys until their heads explode, while Legends of the Dark King is much more focused on Raoh building his empire. Sure, Raoh gets into fights with enemy generals who have their own unique fighting style but it has a very different feel from other shows in the franchise. The animation in this show is also subpar. I realize that the original series has pretty cheap animation but it at least had detailed character designs. With this new series, the characters are pretty basic. The animation should be much better since they're so simple. Legends of the Dark King is decent, but not astoundingly great. Considering this is a Fist of the North Star show, this is disappointing. If you're thinking about watching it, then you might as well, just don't get your hopes up.