Fighting hard in capturing head of legion (8)
I believe the answer is:
battling
'fighting hard' is the definition.
'battling' can be an answer for 'fighting' (battling is a kind of fighting). I'm not sure about the 'hard' bit.
'in capturing head of legion' is the wordplay.
'in' becomes 'batting' (I've seen this before).
'capturing' means one lot of letters goes inside another.
'head of legion' becomes 'l' (I can't justify this - if you can you should give a lot more credence to this answer).
'batting' placed around 'l' is 'BATTLING'.
Can you help me to learn more?
(Other definitions for battling that I've seen before include "having a struggle" , "Struggling" , "Fighting" .)