Before the Crusades
The country that seceded from the United Nations after its ban on technology, instead building the Ultra Dreadnought and becoming an airborne militarized state under the new name "Zepp".
India
The group the United Nations formed to combat Justice and her Gear army, boasting members the likes of Sol Badguy, Ky Kiske, Kliff Undersn, and a pre-gear cell infused Testament.
The Sacred Order of Holy Knights
AKA "Faust", one of his patients mysteriously dies on the operating table and believing he committed some sort of mistake is driven mad becoming a serial killer until he is captured, afterwards regaining his sanity.
Dr. Baldhead
Occurring in 1999, the event dubbed "Dawn of Revival" during which technology all over the world malfunctioned was caused by this entity, also referred to as "mother" by the Valentines.
The Universal Will
This man resigned as leader of The Assassin's Guild in 2168 feeling as though the guild no longer held the ideals it was founded under.
Slayer
AKA "The Original", he discovered The Backyard which is an alternate dimension comprised of all the world's information as well as being the source of magic.
Happy Chaos
The current president of Zepp who, despite not yet appearing as playable, is potentially the strongest character in the series having easily defeated and captured Bedman even though Bedman fought evenly with Sol Badguy and Slayer.
Gabriel
This council formed in 2008, made up of the first magic practitioners who taught humanity how to replace technology with magic shortly after The Dawn of Revival
Sanctus Populi
In 2173, Sol Badguy withdrew from the army fighting Justice, stealing this Sacred Treasure on his way out.
The Fireseal
AKA "That Man" or "The Gear Maker", he created Justice and therefore is considered responsible for The Crusades, though many of The Original's worst deeds during The Crusades are wrongly attributed to him
Asuka R. Kreutz
The name of Sol Badguy's anti-Gear weapon, which after it proves to be too powerful for even himself to wield is split into 8 pieces becoming known as the Sacred Treasures
Outrage
The Crusades ended with humanity's last stand in Rome leading to their annihilation, although this person would rewind history until the result was altered.
I-No
AKA "Sol Badguy", he worked with That Man on the Gear Project before he eventually became the first human Gear test subject.
Frederick Bulsara
The name of the forest Dizzy is left in by the couple who rescued her as an infant and is currently protected by Testament, though they will leave on occasion to visit Dizzy or the Jellyfish Pirates.
The Forest of Demons (or The Grove)
This was the initial name of the "Gear Project", which initially focused on curing terminal diseases and adapting human bodies to extreme environments before turning to weapon development
The Ecosystem Evolution Project
Over the course of the Crusades, Kliff Undersn and Justice fought each other on this many occasions.
16
AKA "Justice", she was a researcher in the Gear Project stricken with an incurable illness and was placed in cryosleep until That Man turned her into a Gear in an attempt to stop the US from making Gear weapons.
Aria Hale
Slayer's ageless wife Sharon, who is constantly sucked dry of her blood to the point of being whisked away by the wind had her immortality explained by series creator Daisuke Ishiwatari as being due to this.
A bug in the Backyard