So Vergil doesn't use guns?

[AlchemistFromEden]

We dont know what kind of twins they are. They have very similar faces, i dont think they are fraternal. Different skin tone could be tan.

fraternal twins can have similar faces, they don't have to look completely different

 

[Martius]

fraternal twins can have similar faces, they don't have to look completely different

Usually even not twin siblings are similar enough to tell that they are siblings. I dont know how Mundus could miss that when they allready know looks of Dante and they got Vergil picture before attacking Order base.