Machiavellian
behind-the-scenes operator
coconspirator
conniver
conspirator
conspirer
counterplotter
eminence grise
exploiter
gamesman
gray eminence
intrigant
intriguer
kingmaker
logroller
machinator
maneuverer
operator
opportunist
plotter
pork-barrel politician
schemer
strategist
wheeler-dealer
wire-puller
beguiler
cheat
cheater
deceiver
slicker
trickster