Possible Clues:

• Serve a piece of toast
• Person serving is 24 across in terms of 1 in play
• Extremely lucky holding animal - a gamble by Fielding
• Join undercover unit as a fighter
• Private Eye, say, infiltrates combine
• Identity reflected in more reliable fighter
• General or private
• Military sort prepared sild and roe
• Persevere, with 'on'
• Low-ranking Mafioso