deputy

ambassador, diplomat, diplomatist, emissary, foreign minister, legate, plenipotentiary

alternate, backup, pinch hitter, relief, replacement, stand-in, sub, substitute, surrogate, understudy

informer, operative, spy

broker, distributor, manager

arbiter, arbitrator, comprador (or compradore), conciliator, go-between, intercessor, intermediary, interposer, liaison, mediator, middleman, peacemaker

mouthpiece, point man, point person, prophet, speaker, spokesman, spokesperson

attendant, handmaiden (also handmaid), maid, maidservant, scullion, servant

auxiliary, legman, subordinate, underling

employee (also employe), hand, help, hireling, laborer, swamper, worker

gal Friday, girl Friday

man Friday, right hand

aide-de-camp