Six Great Nobles

Six Great Nobles (六大貴族) are the six great noble families and the second most influential power faction within the Re-Estize Kingdom behind royalty.

Background
The Six Great Nobles are a political faction within the Re-Estize Kingdom that competes with the Re-Estize Royal Family for control of the nation.

The Bloody Valkyrie Arc
In the Royal Capital, after Gazef Stronoff reports about Ainz Ooal Gown to the King and the great nobles, many of the nobles suspect that this magic caster is in allegiance to the Empire or the Theocracy, and they suggest to detain the magic caster and put him under their control.

The Men in the Kingdom Arc
In the Royal Capital, Princess Renner asked Marquis Raeven, the hidden leader of the Royalty Faction to aid her in suppressing Eight Fingers, and she also told him that Marquis Blumrush had betrayed the Kingdom for selling information to the Empire.

The Magic Caster of Destroy Arc
In the Royal Capital, the Royal Family and the leaders of the Six Great Nobles received a declaration of war on the Re-Estize Kingdom, and the Baharuth Empire demanded them to return E-Rantel and its surrounding area to the Sorcerer Kingdom. This cause a heated debate between the Royalty Faction and Nobility Faction over this mad declaration but they decide to accept the declaration of war despite the Warrior Captain's warning.

Concerning the topic of Ainz Ooal Gown's claim over E-Rantel, the King, the Crown Prince and the Great Nobles gathered for a strategy meeting about it. Marquis Raeven told them that the Empire have mobilized sixty thousand soldiers and they also received a message from the Theocracy declaring their neutrality against Ainz Ooal Gown. This news caused the nobles to suspect the countries as they were all making such an overreaction over a single magic caster and they decided to send five thousand troops to fight Ainz Ooal Gown as an estimation of his power in the war while Marquis Raeven was given total command over the Royal Army.

In the Katze Plains, the leader of the noble faction and the left wing of the Royal Army were consumed by the Sorcerer King's magic and summoned five hideous monsters. During the massacre, the Dark Young slaughter many of the nobles and their levies troops in the plains.

The Ruler of Conspiracy Arc
After the massacre at Katze Plains, Marquis Raeven was left traumatized and retreated back to his domain, with seemingly no intentions of returning. Many noble factions were effectively dissolved, while the other nobles are trying to recover from the massacre.

Strength
The Great Nobles own about thirty percent of the Kingdom. Between them, they controlled enough wealth, land and territory to rival, if not outright surpass, the King. Because of this, they frequently found reasons to excuse themselves from the King’s summons.

Trivia

 * With the deaths of many upper elite nobles, many spares have been elevated, lowering the quality of nobles.
 * In the Anime, none of the Great Nobles were seen following the massacre at the Katze Plains.
 * In addition to that, at least Marquis Boullope and Blumrush are confirmed dead.