Well I have to say that I really wanted to watch this anime after reading the manga volumes over and over again... I love the story behind it and the ova was following volume 1 perfectly. But there is a but in all this.
For a reader like me who had already read all the chapters it's easy to know and understand EVERYTHING that happens, but I'm not sure if a person that haven't read anything would understand certain things here.
Therefore as a reader it's hard for me to know how a person without the background history would look at this great ova. I'd
say it's a great one filled with what i expected.. though a little too much blood for my taste is all.
To tell the truth, ova 1 only contains chapter 1 from volume 1 from the Vassalord manga which contains many more chapters and more than 4 volumes. So if you liked the ova, please do read the manga
Overall I give this ova a 8 because I love the story behind it, the art was great, and loved the voice actors too