Order from Ring - the one sent on The Missions (8)
I believe the answer is:
commando
'one sent on the missions' is the definition.
I can't judge whether this defines the answer.
'order from ring' is the wordplay.
'order' becomes 'command' (commanding is a kind of ordering).
'from' is a charade indicator (letters next to each other).
'ring' becomes 'o' (letter resembling a ring).
'command'+'o'='COMMANDO'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for commando that I've seen before include "Amphibious military unit" , "One soldier" , "Shock troop unit" , "Military unit specially trained for raids and assaults" , "Soldier from elite unit" .)