Acacia, Ichiryu, Jiro and Midora, while they are all Humans, they are all freaking old while appearing to be in their prime. Acacia for some reason is over 600 years old, Ichiryu is over 500 years old, same with Jiro and Midora. I'm not sure about anymore Gourmet Hunters being these old, but these four stands out the most among them all. For any ordinary Humans, trying to live for over 100 years is crazy, but these guys ain't ordinary Humans, they are Gourmet Hunters, so how do Gourmet Hunters live for so many years? Does it have something to do regarding to their Gourmet Cells, or something like that?