=Alucard/Vincent 

 I have noticed a large link directly to FF7. I have played it numerous times and found several secrets including several connecting directly to Vincent. He has a lost love which you can find with the submarine and theres a story on how he was made. The secret for his lost love could translate to Seras Victoria AND/OR Integral Hellsing. This could be reason why Integral has kept him tame. Also Vincent actually looks a lot like Arucard. Vincent and Alucards costumes are very similar.They even use similar wepaons. I think the creator of this anime series was a Final Fantasy 7 fan like myself AND/OR Vice-Versa. 

 Genisis