Group of soldiers, say, devoured by fierce beast (6)
I believe the answer is:
'group of soldiers' is the definition.
'legion' can be an answer for 'soldiers' (I've seen this before). I'm not certain of the 'group of' bit.
'say devoured by fierce beast' is the wordplay.
'say' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'devoured by' is an insertion indicator.
'fierce beast' becomes 'lion' (I can't explain this - if you can you should give a lot more credence to this answer).
'eg' going within 'lion' is 'LEGION'.
Can you help me to learn more?
(Other definitions for legion that I've seen before include "Part of an army; many" , "Roman battalion" , "Body of Roman or French soldiers" , "The French have a Foreign one" , "Large unit of the old Roman army" .)