I did a review of Kim's book for UNRV.
http://www.unrv.com/book-review/huns.php
The majority of the Greuthungi who had remained north of the Danube under Athanaric after the Hunnic war probably remained there when Athanaric sought sanctuary in Constantinople in 381.
It is probably these warriors who were led by Valamer, Theodemer and Widimer as allies of the Huns at the Battle of the Catalaunian Plains in 451