User blog comment:FairyRaven/Fairy Tail Chapter 356: Tartarus arc - Prologue, Review and Commentary/@comment-1359322-20131018133156/@comment-7418318-20131018182106

Despite his disapproving comments about the architecture of their Headquaters, Silver seemed to be quite happy among the other demons.

That's also the possibility that demons and devils are distinct "species" in Fairy Tail after all and silver is a devil slaying demon.

Can someone with good japanese knowledge and access to the RAWs answer that question?

Though that would reminds me so much of the Dungeons and Dragons Forgotten Realm and their Blood war between the Baatezu and Tanarii (or however the demons and devils factions are spelled correctly).