The character of air mingled with fog (6)
I believe the answer is:
figaro
'the character' is the definition.
(I have seen 'Operatic character ' mean 'figaro' so perhaps 'character' could also mean 'figaro')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for figaro that I've seen before include "Beaumarchais hero" , "Barber in Rossini opera" , "The Barber of Seville" , "Mozart's 'Marriage'" , "Hero of Mozart opera" .)