Dark Guilds

Dark Guilds (闇ギルド Yami Girudo) are guilds that are not officially recognized by the Magic Council; therefore, they are treated as criminal organizations. Dark Guilds are typically disdainful of Legal Guilds, seeing that they abide the rules imposed by the Magic Council. Their belief is that the rules of the Council would only limit the full potential of guilds, as they place too many restrictions.

Organization
There is very little information known about the hierarchy of Dark Guilds. All Dark Guilds, like legal guilds, are run by their respective Guild Master. Dark Guilds have S-Class level Mages, but it is unknown if the Mages in question are called "S-Class Mages". In the Grimoire Heart Guild they have a Deputy Commander, or second-in-command, of their guild.

Balam Alliance
The Balam Alliance (バラム同盟 Baramu Dōmei) is an alliance between three of the most powerful Dark Guilds in the world. Despite being referred to as an alliance, the three guilds do not interact with each other at all, and their alliance is nothing more than a non-aggression pact. In X784, they controlled all Dark Guilds, with the exception of Raven Tail. As of year X792, it is officially defunct.

Trivia

 * The word Balam, in "Balam Alliance", is the name of a King of Hell who rules over 40 Legions of demons.