120 gold cost and potentially limitless mercenaries bought in a single city makes them somewhat powerful in the hands of a human player. I'll use an example to illustrate... 5000 gold in the bank - not too hard to achieve (10-15 turns with a mid-game economy). Sail a small landing force including at least one mercenary to the enemy land and conquer one city (as small and undefended as possible). I'll assume that 6 units survive, including the mercenary (more or fewer just make the next quicker or slower). Use the Merc to spread the guild, use all 5 of the other units to buy a mercenary. Next turn, all 10 units buy 10 more mercenaries. Then 20 more. By this point we've spent about 4200 gold on the attack force, but we have 35 mercenaries in the city for a basic strength of 175. Add in Iron weapons and we're at 245. That's going to hurt. Make it Hippus and we've got 35 strength 7 units with Commando and high movement connected to the enemy road network... Possible improvements If a single guild "branch" were only allowed to hire a single mercenary per turn, it would prevent this (similar to old "airlift attack" that was blocked in vanilla) and also increase the value of spreading the Guild of the Nine as multiple branches would allow you to raise a greater-sized force more rapidly. It may be useful to include a random event that allows the hiring of a single mercenary (requiring Currency as a prereq) such that the "non-founding" players have a chance to obtain mercenaries also. If the guild-branches acted as the BtS corporations and provided an income bonus to the head-quarters for each branch, the benefits of spreading the guild becomes greater still, whilst maintaining the flavour. This also preserves the value of obtaining currency first, even if other players can hire mercenaries, you're going to profit from it. Alternatively, each time a civ buys a mercenary, the headquarters could pay out a small sum (10 gold?) to the owning player. "The Illians have hired some of our mercenaries. The Guild of Nine has paid it's tithe to the treasury" To further complicate things, the ability to hire a mercenary may also be limited to civs with which the founder is not at war.