The Black Mercenaries was founded in early August 2008 by Lord Davy Menace, who himself is often cited as one of the four founding members of the player-made EITC (alongside Pablo Swordmaster, Nathaniel Scurvyskull, and Samuel Redbeard). It was one of the first EITC guilds created, along with Pablo Swordmaster's EITC Elites. The Black Mercenaries saw quick success as a "military guild", establishing the company's first army, and establishing the trend of the EITC as a junta organisation.
Maxed and highly active, the Black Mercenaries enjoyed more than a year of dominating the fledgling role-play world, before beginning a state of decline. Lord Davy Menace had hitherto assumed complete control of the entire EITC, and he became the first role-player to use the title "Lord Marshal" (Pablo Swordmaster was leader of the EITC before him, but had never adapted this title).
In mid November 2009, the guild was officially disbanded when Lord Davy Menace suddenly and shockingly went inactive without naming an heir to the guild. Though few theories exist as to his spontaneous disappearance, he would remain inactive until reappearing once again in the summer of 2012. The officers of the guild failed to keep the Black Mercenaries alive in Menace's absence, and thus broke off to create or join new EITC guilds, including the Co. Guard, the Black Council, the Black Empire, the King's Mercenaries, and the Co. Empire.
Though not the oldest EITC guild, the Black Mercenaries was certainly one of the first, and spanning almost a year and four months, was one of the longest-lasting guilds to date. They were the first EITC guild (and also the first role-play guild) to establish and utilise a rank system – the EITC Elites had only operated off of the default officer-member system. The Black Mercenaries assigned custom titles and positions to its members, and was also the first EITC guild to have an established first-in-command, second-in-command, third-in-command hierarchy. The guild was also roughly divided into the "army" and the "government" – another first that would be used by many guilds down the road. Examples of ranks existing in the "army" portion of the guild included general, admiral, et cetera; government titles varied from governor of a given island to members of the lord marshal's ministry.
Though few records exist of the EITC Elites, the Black Mercenaries was likely the first role-play guild to utilise a democratic voting system amongst its guild, for elected titles and even officership.
The Black Mercenaries is often cited as the "first great EITC guild", and their reign in the Caribbean is referred to as "the Bronze Age" (as opposed to the "Golden Age" of the Co. Empire and the "Silver Age" of the Co. Black Guard). With the first official army the EITC had seen, guildmembers were organised and given ranks, assembled in squads and firing lines, and commanded by officers in some of the EITC's first battles against piracy and rival guilds. The guild was also the first cited guild to wear the traditional EITC uniform (which included the dark blue long coat acquired from Adoria Dolores's quest, and the admiral hat), a trend that would be continued in the EITC until the game's closing.
A few notable officers of the Black Mercenaries would later go on to have impacts on the EITC. Such alumni include: Ben Costello (zealous EITC commander and controversial officer in the early days of the Co. Empire), Chris McHayes (founder of the Black Empire and Lord Marshal of the EITC following Lord Davy Menace's disappearance), Jeremiah Garland (EITC veteran known for his later work in the Co. Empire and the Co. Black Guard), and Poseidon (founder of the Co. Guard famous for his attempted takeover of the EITC against Chris McHayes and Benjamin Macmorgan).
- Though the Black Mercenaries did not fight any official wars against piracy, they did suffer from some minor insurrections, including a failed plot to overthrow Menace led by Poseidon, Costello, and Garland.
- The designated guild base was the smuggler's cellar on Rumrunner's Isle – not quite big enough for a company meeting but secretive and seldom visited by outsiders.
- As a joke, Lord Davy Menace once attempted to persuade his officers that he had once served in the infamous NPC guild the Marceline Guild, before betraying the order and siding with the EITC; several officers believed him.
- It was a set rule that all officers of the guild must own at least one ship called the Black Mercenary; though not usually a guild law, the custom of naming ships this was continued for several years in the EITC.
- The last known person to have been in contact with Lord Davy Menace before his sudden disappearance was Jeremiah Garland, as the two were levelling one night in Las Pulgas, Padres Del Fuego, before Menace's inactivity the following day; many subsequently theorised that Garland had "assassinated" Menace, or that he indeed was Menace incognito. Both accounts are false.
- Though with their meeting location on Rumrunner's, the Black Mercenaries operated mostly out of Port Royal, before the update that majorly changed the appearance of the island.
- Others who have claimed to be former members in the Black Mercenaries (though no apparent evidence exists) include future EITC leaders Cad Bane, James "Usman" Strider, and James Dreadhawk.