Small monarch involving one military group with his scrappy, scrappy fighting (11)

I believe the answer is:

skirmishing

I'm a little stuck... Click here to teach me more about this clue!

'fighting' is the definition.
(skirmishing is a kind of fighting)

'small monarch involving one military group with his scrappy' is the wordplay.
'small monarch' becomes 'skiing' (I am not sure about this - if you are sure you should believe this answer much more).
'involving' means one lot of letters goes inside another.
'one military group' becomes 'RM' (Royal Marines).
'with' says to put letters next to each other.
'scrappy' indicates anagramming the letters.
'his' with letters rearranged gives 'ish'.
'rm'+'ish'='rmish'
'skiing' placed around 'rmish' is 'SKIRMISHING'.

'scrappy' acts as a link.
This may not be right. It may belong to another bit of the clue.

Can you help me to learn more?

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.