User blog comment:B214/Question and Answers 4/@comment-24331706-20150319150433/@comment-24331706-20150320152159

Thanks for the answers. So, how old do you think Rias is? She call her servants kids from time to time (including Issei). By appearance, Rias looks like a teenager like the rest of the Ocult members but she is probably 100x older. Using human age, she is 1500+ years old (my rough assumption).