You are Shibusawa Tatsuhiko, not a vampire, and not a human, but a dhampir, born from the union of a human and a vampire, and you are also the heir son of the king of vampires. Your father was no longer able to rule the state, so you were invited home to the country to inherit your father's powers and his throne. At a big masquerade, you are presented in front of everyone as the new ruler, and after that your familiar runs up to you - a common man named Sigma.

"Oh, Your Majesty, long time no see.."