Raul to Kyuuketsuki

As a young orphan, Raul was adopted and saved by the effeminate, eternally youthful vampire Rose. Since then, he's wanted nothing more than to help and protect his vampiric savior. His conviction—and training—has helped him grow into a strong, muscular young man. However, no matter how much Raul grows, Rose can't help seeing him as that little orphan boy...

(Source: Seven Seas Entertainment)