User blog comment:B214/Question and Answers 2/@comment-4547267-20140402005017/@comment-1359322-20140402043956

No i think Rias and Sona are real friends, maybe even best friends but like you said, there is a major difference between Sona and Akeno's friendship with Akeno. Sona is Rias' best friend who is also her rival while Akeno is Rias' best friend who is her most trusted person.