Am I Really the Protagonist?

After an accidental death, he came to a different world and became Izumi Sagiri's brother. Both his parents were 'dead', he had a house and a sister, and he was a copycat. It was simply a setting for a winner in life! But what he didn't expect was that this world seemed to be more than just a sister setting. Are the ghouls attacking people again? Did the elf girl cause space earthquakes again? Oh, the great onmyoji in Tokyo has been busy fighting against a certain interstitial great monster recently, so he has no time to care about these things. But why does something seem wrong with the chefs in this world? Is the cooking equivalent to BUFF? Improve people's physical potential? Can the best cuisine even satisfy a ghoul? So... Am I really the protagonist? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.