Oración Seis

The Oración Seis (オラシオンセイス Orashion Seisu 六魔将軍 lit. Six Demon Generals or Six Demons) was a Dark Guild comprised of six incredibly powerful mages. It formed a third of the Balam Alliance.

Goal
Their goal was to retrieve the Dark Magic "Nirvana" which was capable of turning "light" (good) into "dark" (evil). In other words, if this magic was acquired, they could turn members of good guilds against each other and bring forth total chaos. They were, however, eventually defeated by the Light Team after initially crushing them.

Location and Buildings
When one of the Oración Seis members, Cobra, was first shown, just before the Oración Seis arc, he was in what appeared to be a huge fortress or castle. This fortress was presumably the location of their main headquarters.

Later, when they came to search for Nirvana, they resided inside a cave, which was actually residue of the Nirvit capital. It was destroyed by Natsu.

Strength
As a member of the Balam Alliance, Oración Seis possessed incredible magic power at its disposal. The six members of the Oración Seis alone supported a third of the entire Balam Alliance, which controlled virtually all the Dark Guilds. It was stated that every single member of Oración Seis was strong enough to take down a single guild. Collectively, they were able to quickly defeat the numerically-superior Light Team (mainly: Jura Neekis and Ichiya Vandalay Kotobuki) without much effort, a feat made even more impressive by the facts that their leader was merely watching the skirmish and their trump card was asleep. Their power in conjunction with their maliciousness forced the Guild Masters of the most powerful legal guilds to create an alliance capable of opposing them.

History
The guild was created by a man who called himself "Brain". He took five children, former slaves from the Tower of Heaven who possessed the highest magical potential there, and raised them to be members of the Oración Seis (and also made them his keys, which served the purpose of sealing his even-more-sinister alter-ego, Zero). Ultear was considered at one point to be either used for Brain's Body-Link Magic or to be one of the Oración Seis, but Brain decided that Ultear's magic was too great that it did not need to serve his purpose.

Trivia

 * Rave, one of Hiro Mashima's previous works, also features a group named the 'Oración Seis'.
 * All of the Oración Seis members' name are codenames. Hoteye is the only member of Oración Seis to have his true name revealed (Richard).
 * The Oración Seis' crest is formed by the characters "六マ", the Kanji for "six" and the katakana "Ma", which means "Demon". Thus, the members were also called "The Six Demons".
 * Hiro Mashima stated that 'Oración Seis' was only a codename for this nameless guild, but with the closing on the deadline and lack of a better name, he decided to go with the same name.
 * In the anime, all members of Oración Seis, except Brain, appear in Erza's flashbacks during the Tower of Heaven arc.
 * In Spanish, its name translates to "Prayer Six", and each member incidentally has a "prayer" which they reveal after they are defeated.