Khaos Brigade

The Khaos Brigade, also known as the Army of Disaster, is an organization in High School DxD. The Khaos Brigade consists of multiple races: Devils, Fallen Angels, Humans (who are descendants of legendary/mythological heroes), and a few (unfallen) Angels. They are the main antagonists of the light novels from the Birth of the Breast Dragon Emperor arc to the Heroic Oppai Dragon arc.

History
The Khaos Brigade was created by Ophis, the Dragon God of Infinity, with the sole purpose of removing the Great Red, the most powerful Dragon in existence known as the True Dragon, out of the Dimensional Gap.

The Khaos Brigade introducing themselves to the world and attacking the leaders of the Christian religion's Three Factions. Shortly after that, the Khaos Brigade began to start many terrorist attacks, such as attacking the VIPs during Rias' Rating Game against Diodora, kidnapping the Youkai leader, Yasaka, and committing many other atrocious acts.

Later the Hero Faction betrayed their leader Ophis after Cao Cao, the leader of the Hero Faction, sided with Hades, the God from the Realm of the Dead, and used Samael to steal most of her powers under the intention of creating another Ophis. This has resulted in the latter remaining in a presumed powerless state. However, Ophis released her powers in the form of snakes before Cao Cao came to steal her powers. As such, Ophis did not lose most of her powers.

Vali Team
The Vali Team is a special team of the Khaos Brigade led by Vali Lucifer, the descendant of Lucifer and the keeper of Albion, the White Dragon Emperor and the arch-rival of Ddraig, the Red Dragon Emperor. The Vali Team is not connected to any of the factions of the Khaos Brigade and it acts independently.

The Vali Team are currently considered as traitors by the Khaos Brigade after they secretly sent Ophis off to the Gremory Team and are currently wanted by both the Alliance and Khaos Brigade.

Members

 * Vali Lucifer Leader of The Vali Team
 * Arthur Pendragon and Le Fay Pendragon, siblings who are the descendants of King Arthur and Morgan le Fay
 * Bikou, the descendant of the first Monkey King, Sun Wukong.
 * Kuroka, Koneko's older sister and a wanted Stray Devil
 * Fenrir, a giant wolf who is the son of Loki.
 * Gogmagog, a golem from English folklore.

Old Satan Faction
The Old Satan Faction is the largest faction of the Khaos Brigade consisting of Devils who are descendants of the original Satans: Beelzebub, Lucifer, Asmodeus, and Leviathan. They are the only group of Devils who resist using the Evil Pieces, as they believe them to be a disgrace to Devils because they reincarnate Humans and other races into Devils. They are also against the Devils' current system, and they seek to change it by overthrowing the current Satans. The leaders of the Old Satan Faction are Katerea Leviathan, Creuserey Asmodeus, and Shalba Beelzebub.

All three leaders of the Old Satan Faction were defeated and a majority of its major forces were terminated by Ajuka Beelzebub, further weakening their faction, and rendering them incapable of taking any further action.

Members

 * Katerea Leviathan Leader
 * Creuserey Asmodeus Leader
 * Shalba Beelzebub Leader

Hero Faction
The Hero Faction is the second-largest faction of the Khaos Brigade led by Cao Cao, the descendant of Cao Cao from the Chinese novel Romance of the Three Kingdoms and the one who betrayed Ophis. It is a faction of the Khaos Brigade that is allied with Hades, the God from the Realm of the Dead, and it is also the most dangerous faction of the Khaos Brigade due to its members being Sacred Gear, Holy/Demon Sword, and Longinus wielders.

Aside from the main members, there are also a large number of Sacred Gear wielders who were abducted and brainwashed. Many of these members, however, were sacrificed in battle during the Hero Faction's attempts to force them to achieve Balance Breaker. All those who didn't reach Balance Breaker were eventually captured and later died as a result of Ophis' snakes destroying their Sacred Gears, while those who did achieve Balance Breaker were called back before they could be caught.

The Hero Faction was greatly weakened after the loss of their leaders. Indra sends their most powerful members (Cao Cao, Leonardo, and Georg) to the Realm of the Dead, taking all of their Longinus from them. Jeanne and Heracles were captured by the Devils and Fallen Angels for interrogation, while Siegfried was the only main member of the Hero Faction who died in battle.

Members

 * Georg the descendant of Johann Georg Faust, the human who contracted with the legendary Devil Mephisto Pheles.
 * Siegfried the descendant of the dragon-slaying hero in Nibelungenlied.
 * Jeannethe descendant of the Maiden of Orléans, Joan of Arc.
 * Heracles the descendant of the Greek mythological hero, Heracles.
 * Freed Sellzen