Rosario + Vampire is one of those stories that changed quite dramatically between its manga and anime forms.
The anime can best be described as a guilty indulgence of many fans, and it delivers plenty of genuine humor and silly laughs despite being a fan service-laden reflection of the modern trend toward harem comedies.
Its manga, by contrast, is closer to what you'd find in Bleach than Demon King Daimo. It's a more serious affair that swaps out much of the fan service for overly long, dramatic fight scenes between Tsukune's pals and a never-ending cavalcade of monsters .
Well, maybe not *quite* never-ending.
Rosario + Vampire: Season II is set to receive an epilogue chapter in Shueisha's Jump Square magazine on April 19th - a month after the final chapter is scheduled to run.
The ending of the series is definitely an abrupt one, given that Akihisa Ikeda began his work on Rosario back in 2004... but apparently he had a bit more story to tell and was eager to move on to other projects.
Whether those projects are something entirely different from the monster-laden world of Rosario or are the beginnings of a third chapter remain to be seen - and are probably contingent on what happens in the epilogue chapter.
Those following the manga don't seem to be holding their breath for Chapter III, however, so it looks like the anime fanbase can give up on their petitions, change.org campaigns, and Facebook groups and warm up to the fact that the story's ending.
Or, y'know, they can just keep making fan trailers and hope for the best...