I then watched the OVAs, thinking they would be similar, but they were completely different. The characters mostly have similar but noticeably different designs and similar but noticeably different personalities, with thee exceptions being that some have completely different personalities to the point of being unrecognizable at first, such as Lin. On top of that, there is a new character Kirihiko that just fits in with the rest of the group. Furthermore, the tone, atmosphere, style, etc. are all different being much more light hearted, wherein the main series felt rather dark. They also had a very different structure, focusing on random adventures with Murasaki and other side characters, with the side characters also getting some decent development. All in all, I liked these OVA's better than the main series, since they were focused on what the best part of the main series was but with a tone, atmosphere, and structure that better fit it. And as far as I understand it, these are closer to the manga/LN, so I suppose I have something to look forward to in that regard.
tl;dr: A work that while based on the same source material, is pretty different, and that benefits from being so.