Yes, they did make a series called Urotsukidoji II. Stay away from it. The incredible acting and animation that made the original series kick ass simply isn't there, making for a rather lame rendition whose only real ties with the original are the tentacle fucking. Not that any fan of Urotsukidoji has anything against tentacle fucking, but that wasn't what really made it shine.

As far as the original six go, you don't get much better than this. The animation is a ten; the plot is superb, the acting is cool and you can't help but appreciate whatever sick fucker thought these up.

Oh, as an interesting sidenote: There are several sound bites from Urotsukidoji used on the White Zombie album La Sexorcisto: Devil Music Volume 1. See if you can spot them!