Hah! I see. Well, my suggestion is read the manga before watching the OVA. OVA is good for animated fights and that is all.

As you can see by the two volumes, its a bit different from the Anime. Alucard to Seras...is like a harsh dad and he's like knight in shining armor/bitchboy to Integra since day one. The change in their meeting makes for a different direction in the future.