Thirteen Night Swords

Thirteen Night Swords (十三の夜剣) is a secret society formed by thirteen major aristocratic families who covertly maintain great influence over the Midgar Kingdom with help from the Cult of Diablos. It is essentially, a small convention group that runs the kingdom from the shadows.

Overview
The Thirteen Night Swords are an collective of exclusive social circles for the most influential aristocratic nobles from Midgar Kingdom who secretly control the country by possessed immense wealth and control many territories within the Kingdom. Due to their aristocratic status, the members of the organization can abuse their authority without any repercussions allowing them to commit any crimes while leaving unpunished.

History
Thirteen Night Swords are an aristocratic secret society that is said to control all the royal courts of Midgar Kingdom from the shadows, which have been ruled by the thirteen great noble families. Apparently, Thirteen Night Swords have a building collusive relationships with the Cult of Diablos.

Membership
The Thirteen Night Swords are a group of corrupt nobles, comprised of thirteen great noble families who banded together and formed an alliance to which they swore loyalty to the royal family while, in reality, secretly engaging in power plays.

Bloody Midgar Serial Murder Terror
Following an incident at Midgar Royal Spellsword Academy, Eliza, a noble and daughter of Duke Dacuacain, was to be put on trial for causing the deaths of several students. Duke Dacuacain used the Night Swords' influence to keep his daughter from being imprisoned, all the while the Night Swords started preparing assassinations on key witnesses for the trial, including Christina Hope and Kanade.

One night, as Count Goethe Moono was preparing false testimonies and bribes to stop Eliza's trial, he was attacked by a man wearing a clown costume. The count, along with his entire security, were killed with the staff being the only survivors to report the story.

The next day after, the Night Swords learnt about Goethe's death which caused them to prioritize in eliminating Christina Hope and Kanade instead, with Christina's father giving them his full permission. Count Kuzaya and Baron Grehahn, who were assigned the assassination mission, were the next victims of the same mysterious clown and were killed in their underground room. The clown hung their bodies at a fountain, leaving a message to reveal to the public his name, Jack the Ripper and his intentions to hunt down the rest of the Night Swords.

On the night of the third day, Oyano Bow, Viscount Jet and Marquis Jet headed to Hope manor to eliminate Christina, bringing a small army of assassins to help them. Like before, they were all killed by Jack.

The remaining Night Swords regrouped at Count White's mansion to set up a trap for Jack the Ripper. They lured him straight to the Night Swords' underground colosseum where a massive force of the best mercenaries and Dark Knights, and a monster Duke Dacuacain procured from the Cult of Diabolos's Loki Faction, were ready to take the clown on and kill him. They also erected a barrier around the arena to prevent the clown from escaping.

To Night Swords' horror however, not only did Jack turned the arena into a literal bloodbath but he also somehow escaped the barrier to confront them. Jack eliminated the Night Swords one by one, with Count White and Duke Dacuacain being the lasts to meet their end.

Legacy
Once word got out that all of the Night Swords had been killed, it didn't take long for the rest of Midgar to take immediate action against the deceased men's families, with Duke Dacuacain's family taking the full brunt of it as all their wealth and resources had been confiscated by the Knight Order before they were kicked out of their mansion.

Duke Dacuacain's daughter, Eliza vowed to rebuild the Night Swords however her and her dreams were cut short when Christina Hope, having become the second Jack the Ripper, killed her as her first act in her war against corruption.

Trivia

 * Isaac's family is presumably a member of this society.