I can get all 13 during action phases of a single turn.
Setup: 1 Tormentor in supply, 9 in your deck, 10 Villas in the supply, Lighthouses in play for each opponent, You have 84 Coin Tokens
Play 2 Madmen so your hand contains 9 Tormentors, 4 Overlords, 1 Ambassador
Repeat 10 times:
Play Tormentor (or play Overlord as Tormentor), gaining an Imp
Buy Travelling Fair, Bonfire (trashing Tormentor), Villa
Play Tormentor, gaining an Imp
Play Ambassador, returning 2 Villas to the supply (you had spare actions from the Madmen)
Buy Travelling Fair, Bonfire (trashing Tormentor and Ambassador), Villa
Play Tormentor, gaining an Imp
Buy Travelling Fair, Bonfire (trashing Tormentor), Villa
Play Tormentor, gaining an Imp