Seven Kin of Purgatory

The Seven Kin of Purgatory (煉獄の七眷属 Rengoku no Nana Kenzoku) is the strongest team of the Grimoire Heart Guild.

Overview
The team consists of seven extremely powerful, deadly Mages, who have each been personally trained and raised by their Guild Master, Hades. Because each one of them is able to use Lost Magic, Hades considers them unbeatable. Even Yomazu, a Mage who was able to fight on par with, and temporarily overwhelm, Gajeel Redfox, a Mage renowned for his phenomenal strength and fighting prowess, claimed that before the Seven Kin, he stood no chance, not even against a single one of them. They are the Dark Guild's main attack force and are the primary reason that Grimoire Heart reigns over the other Dark Guilds as the strongest.

Members

 * Ultear Milkovich - The manipulative, mysterious daughter of Ur is the eldest of the Seven Kin of Purgatory, as well as their former leader before her defection with Meredy. Her lost magic is Arc Of Time.
 * Zancrow - An arrogant and violent young man who is prideful of his Guild's strength. His magic is God Slayer Magic.
 * Capricorn/Zoldeo - A tall, emotionless goat-like member who has authority over Yomazu and Kawazu. He is later revealed to be the Celestial Spirit Capricorn. He was possessed by a Dark Mage named Zoldeo, who desires to return to his human form after accidentally possessing Capricorn.
 * Rustyrose - A sadistic, yet poetic, bespectacled man dressed in fancy designer clothing. His magic is Arc of Embodiment.
 * Kain Hikaru - A large and overweight, albeit very strong, clumsy man with a speech disorder.
 * Meredy - A petite, young girl who views Ultear as a mother figure.
 * Azuma - A stern and muscular man who seeks worthy opponents to fight. His skills are almost the same to Erza. His magic is Arc of Trees.

Find the keys to Zeref's seal
The Seven Kin of Purgatory, throughout the years, searched for magical keys that were said to be able to "awaken" the infamous Dark Mage, Zeref. They managed to find all of them, however, it was later revealed, by Zeref himself, that the keys' ability to awaken The Black Wizard was merely a myth forged by his worshipers.
 * Status: Success

Infiltrate Tenrou Island
The Seven Kin of Purgatory were assigned to infiltrate Tenrou Island and defeat all of the Fairy Tail members, as well as to capture Zeref along the way. Ultimately, the mission was a critical failure. Zeref escaped, and, in the end, Rustyrose and Kain remained the only active members out of the Seven Kin of Purgatory.
 * Status: Failure