Despite a run of extremely good newer anime series (such as Ghost in the Shell: Stand Alone Complex and Samurai Champloo), the vast run of anime still seems to be stuck in plot less limbo. Ninja Scroll: the Series is no exception.
Despite being based on a fantastic anime feature film filled with intrigue, fascinating characters, and amazing artwork, Ninja Scroll falls astoundingly flat as a continuing series. Considering the writing and directing are done by entirely different people, this is no surprise; it is, however, vastly disappointing. Jubei devolves from a witty, sarcastic character to a poorly-written shadow of his former self, complete with bad dialogue. Where the Eight Devils of Kimon were fresh, original villains with an interesting theme, the villains in the ongoing series are just an endless list of "I have this power, and I die by the end of the episode" throwaway thugs. The plot (or lack thereof) is not at all engaging, the heroic characters aren't worth watching, and you find yourself wishing the episode was already over five minutes in.
Do yourself a favor and watch the original film, and don't bother with the pale imitation that is this series.