Extremely devious setter's rising in value — Logodaedalus, say (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

[ 1st and last letters of ( Extremely ) “ devious ” + reversal of ( …’s rising ) I’M(setter is/I am, with the setter using the self-referential pronoun)] contained in ( in ) WORTH(value/merit).