There doesn't seem to be anything on this anywhere. All the other Iron Banner weapons have names with some lore.
All we can glean from this one is that whatever an ashraven is, it can fly. Unless 'flight' symbolizes some one running away or escaping from something.
??
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Ashraven: the name given to one of the last surviving species of bird on Earth after the Collapse- the crow. They travel through ruins and dead zones picking over carrion. Every day is like an all you can eat buffet.