The Four Kings of VOLTS
VOLTS - The group led by Raitei (Ginji) who ruled Mugenjou after Teshimine Takeru disappeared. It consists of regular squads of fighters, led by the 4 Kings: Fuuchouin Kazuki, Kurusu Masaki, MakubeX and Fuyuki Shido. After Raitei was defeated by Ban, Ginji left Mugenjou and VOLTS disbanded.
MakubeX
Found in a sack as a child, only his last name, 間久部(Makube), is known (it was written on the bag). As time went on, he was discovered to be somewhat of a genius, capable of manipulating computers to do whatever he pleased. After a while, he was rechristened MakubeX, the 'x' symbolizing an unknown variable. During the 'Infinity Fortress' arc, the GetBackers are hired to retrieve the mysterious 'IL' from him. It is later discovered that IL is in fact an implosion lens, one of the most crucial parts of a nuclear weapon. At a young age, MakubeX had discovered that all actions in Infinity Fortress were in fact controlled by the 'god' of Babylon Tower, the top area of the fortress. Realizing this, MakubeX decided to give the god an edict: Turn back time to the time of the rule of Volts, or Infinity Fortress will be destroyed. MakubeX worked together with Kakei Sakura very closely to create his bomb. In the manga, it is noted that he, along with Ginji, are the "children of Babylon City's god."
Shido Fuyuki (冬木士度 Fuyuki Shido)
Known as the Beastmaster, Fuyuki Shido is now a rival dakkanya (retriever). He's a friend of Ginji's but hates Ban.
First introduced as the Beastmaster, he has the ability to control animals, although perhaps it should be better stated that he asks them for favors as he views animals as his friends. Once Volts disbanded, Shido left the Infinity Fortress to make a living outside, like Ginji. After reconciling with Ginji (whom he felt had betrayed Volts by leaving Mugenjou), Shido took a cue from the Get Backers and started his own retrieval service - occasionally aided by Emishi. He is very independent and cold to others. Even though his powers allow him to control animals, he considers them friends, and tries to protect them as they do him. He eventually ends up living with Madoka Otowa, and he has an ongoing rivalry with Ban (His nickname for Ban is "snake b*****d", while Ban's retort is often "saru-mashi" [monkey boy] or "pimp" [due to his stay with Madoka]).
Kazuki Fuuchouin (風鳥院花月 (かづき) Fūchōin Kazuki)
The scion of the noble Fuuchouin family and known as "Ito no Kazuki" (絃の花月, "Kazuki of the Strings"), Fuuchouin Kazuki is a frequent ally of the GB duo.
Kazuki is the scion of the noble Fuuchouin family, and his fighting abilities derive from the family school, which emphasizes on grace(麗). He is graceful and charming, and is often mistaken for a woman because of his long hair and feminine face. But when angered, his fury is such that his other title is "Terrible Prince". He's also one of the characters who are freqently drawn in chibi form, as he's sometimes looks like a woman.
His family house was destroyed, and his family killed, in a mysterious fire when Kazuki was in his early teens (which was revealed to be an attack by an enemy clan, who uses black strings); he subsequently fled to Infinity Fortress with Juubei Kakei and Sakura Kakei, where he led a gang known as 'Fuuga' (風雅 Fūga, translation: 'Elegance') before joining Volts beneath the Lightning Lord. He left the Infinity Fortress after the departure of Ginji and Shido, leaving Juubei behind. However, the IL retrieval brought them back together. Kazuki is usually an ally of the GetBackers, due to his friendship with Ginji. He and Ban tolerate each other, but are not close [Ban's unflattering nickname for him is "Ito-maki" (thread spool)]. As the leader of Fuuga, he once ascended into the Beltline to test his strength. At that time he was only able to survive for a week, but during that time he gained the nickname the "Terrible Prince" due to the cruelty he exbited in order to survive. The cruelty was induced by the "Stigma" his left eye carries, as a sign of time lost to the Beltline.
Masaki Kurusu(来栖征 Kurusu Masaki)
He is the last member of those who were known as the Four Kings during the era of VOLTS. His techniques allow him to control light, bypassing any physical defense and inflicting internal damage. He is also able to use light to blind his opponents' senses. Kagami refers to him as the "Brain Trust's Masaki Kurusu", so it is safe to assume that he too was a resident of Babylon City and hopes to re-enter his home with the help of the three keys. In the anime, his alliance with Babylon City is stated openly; he kidnaps MakubeX on their orders and reveals that he had been spying on Raitei and Volts for Brain Trust while he was one of the Four Kings, despite having been a close friend of Teshimine Takeru, who found and raised Ginji in Mugenjou as a child. He is also one of the bearers of the 'Stigma'. In fact, it was he who taught a young Kazuki how to suppress the power of the 'Stigma'.
