[quote]Are weapons that are effective against demons also effective against other mana entities such as dragons, avatars, angels, deities, and djinn?[/quote]
In general as a rule: presumably.
Avatars/Angels/Deities: Don’t think anyone has ever lived to report on this one.
Djinn: Depends on what you wish for. They tend to be a lot more insubstantial than the rest of us, but that’s because of their weird nature. But I’d think that anything that works trans-asterally i.e. stuff that works on ghosts, spirits, demons, etc. “should work” at least to some extent.