Okay so those are good .good. 

And th as cool, Alex has an odd view on humans, but he has lived with them so long he understands coexistence. And Billie could. She has so much knowledge of it and being in Lucifer's circle, of course she'll know all sorts.of languages.

And he'll knights are stronger than regular demons. Like how in angels you have seraphim, arch angels, regular angels and such, a hell knight would be the equivalent to a seraphim. So there would be one more rank above them that are stronger. And all hell knights know the old languages because they use them regularly since old demonic, especially, is a language used by so few. It'll also be interesting when they see Azrael's brand on his hand matching the one on Billie's ribs. Ha ha!