User blog comment:Bennia Lover/Age of Characters/@comment-31137559-20170509041801/@comment-30924344-20170509081322

Rias’s Dad says to me like how a father would say to his son.

“Ise-kun, remember it very well. That man is the actual man standing at the top of the Great-King faction. You can say that the political influence he has is greater than Sirzechs. After all, he is a man who has been watching over the Underworld ever since the beginning of Devils. The years he has lived are far different to us. If the Four Great Maous such as Sirzechs and others are the light of the Devils than that man called Zekrum Bael-sama is the shadow of the Devils.”

Devils/demons are always said to have existed since the beginning of time. All the first fallen angels are around 10,000 years old too as they were the first of their kind.