Thread:Bennia Lover/@comment-1359322-20170508111705/@comment-30924344-20170508113915

Quoted from Tengen in regards to the adult devils and older devils then Rias, sona etc "Azazel did say, in vol. 21, that Sirzechs and the rest of the current Satans still practically kids since they "haven't even lived 1,000 years yet."

So we know that Sirzechs and Ajuka (and Serafall & Falbium) are less than 1,000 years old, but older than 500.

This means that a Devil is still considered very young until they reach 1,000 years. So that means that Devils like Zeoticas, Venelana, Lord & Lady Phenex, and other "adult" Devils are over a couple thousand years old."

Why Sirzechs and co are over 500 is because Zeoticus' Bishop was reincarnated in 1506 and Ajuka had to be alive then to have created the evil pieces.

Also from Tengen "We do know that Rossweise was at least 20 by the time of vol. 9, since she was drinking alcohol with Azazel (the legal age in Japan is 20). Rossweisse is a rule/law-abiding person, so she wouldn't drink alcohol" if she was under-aged, even if someone provoked her.