I've always wondered what the Mercenaries Guild was, and to dismay I discovered their secret with the help of the website/encyclopedia/blogging_webiste wikipedia. I had to find the link between a Mercenary and a Guild, and I felt that Wikipedia would be the only way to do that.
I typed in Mercenary on Wiki, which brought me to its own page. I used the links found on this page to link me to some sort of information on a Guild, and I found it using this sequence:
Mercenary - Battle of Stamford Bridge - William I of England - Tower of London - Oxford - Guild
My conclusion: The Mercenaries Guild has a direct connection to Medieval England, with all clues point towards a connection with the Normans. Now with the connection with the Tower of London and Oxford, they must be cruel yet scholarly folk who live in Oxford England. At my best guess, they plan to take over tremulous as they did with England.
Now, seeing as I had to visit 6 pages to find information on a guild, it is my conclusion that 6 members from MG will rise up and attempt to take over tremulous, but luckily I foiled their plot before they could put it into action.