The Alliance of Hell was officially formed in Volume 25, after Hades holds a conference at Cocytus to invite the gods that agreed to his plans such as Erebus, Nyx, Tartarus, and Angra Mainyu. They began to discuss about the Cross Times Kiss that was led by Mitsuya Kanzaki and received a warning from Issei Hyoudou on attacking his parents, which shook up some of the members.
In True Volume 1, Nyx attempted to use Ingvild Leviathan and her Longinus, Nereid Kyrie, to control powerful dragons like the Two Heavenly Dragons, Ophis, Great Red, and Crom Cruach. However her plan failed as she was defeated by the combined efforts of Issei and Ddraig, who eventually handed her over to Apollon, the current chief-god of Greek mythology, to determine her punishment.
In True Volume 3, Erebus attacked Kyoto, in order to bring disorder to Kyoto's Ley lines out of spite toward Enma for not joining their alliance. He was defeated by Issei, but not before placing a curse on the latter in order to temporarily seal Ddraig's manifestation. Afterwards, Tartarus attempted to drag DxD into the Abyss, but Ophis and Lilith arrived with Ryuuteimaru so Issei could attain AxA and defeat Tartarus alongside Ddraig.
In True Volume 4, the Alliance of Hell took over London with the assistance of Meredith Ordinton, turning it into a stronghold for the Alliance of Hell, as they prepared for the final clash with Team DxD and their allies. Each of the members of the Alliance faced the members of DxD as Angra Mainyu's Evil Dragons faced off against the Two Heavenly Dragon (Ddraig and Albion) as well as Crom Cruach, while the Super Devils Balberith and Verrine faced off against Sairaorg Bael and the Occult Research Club respectively, and Meredith Ordinton faced Le Fay Pendragon and her group. The last two Gods of Hell faced off against the Two Heavenly Dragons (Issei Hyoudou and Vali Lucifer) as well as Fenrir and Gogmagog. With Hades and Angra Mainyu's capture, the Alliance of Hell was disbanded.
The group functions as a terrorist cell with the purpose of eliminating the Longinus users as they deem them a great threat and to eliminate the leaders of every mythological world. They have also created an army of artificial devils in order to defend their world against the invaders from the ExE world that are approaching Earth.
|Hades||Hades is the leader of the Alliance of Hell, known as the God of the Underworld||God||God||Alive (Imprisoned)|
|Angra Mainyu||Member of the Alliance of Hell from Persian mythology, known as the God of Darkness and Evil||God||God||Alive (Imprisoned)|
|Tartarus||Member of the Alliance of Hell from Greek mythology, the Primordial God of the Abyss||God||God||Alive (Imprisoned)|
|Erebus||Member of the Alliance of Hell from Greek mythology, the Primordial God of Darkness||God||God||Alive (Imprisoned)|
|Nyx||Member of the Alliance of Hell from Greek mythology, the Primordial Goddess of the Night||God||God||Alive (Imprisoned)|
|Aka Manah||A Evil God serving under Angra Mainyu||God||God||Deceased|
|Lilith's Children||Devils created by Hades from using Lilith’s flesh and Book of Lucifer||N/A||Pure-Blooded Devils||Active|
|Gressil||A Devil created by Hades from using Lilith’s flesh and Book of Lucifer||N/A||Pure-Blooded Devil||Deceased|
|Sonneillon||A Devil created by Hades from using Lilith’s flesh and Book of Lucifer||N/A||Pure-Blooded Devil||Deceased|
|Grim Reapers||Grim Reapers that are loyal to Hades||High-Class/Middle-Class/Low-Class||Grim Reapers||Active|
|Fake Ddraig||A Evil Dragon copy of the Red Dragon Emperor, the Welsh Dragon Ddraig, who was created by Angra Mainyu||Evil Dragon||Dragon||Deceased|
|Fake Albion||A Evil Dragon copy of the White Dragon Emperor, the Vanishing Dragon Albion, who was created by Angra Mainyu||Evil Dragon||Dragon||Deceased|
|Aži Dahāka II||A clone of the original Aži Dahāka, who was created by Angra Mainyu||Evil Dragon||Dragon||Deceased|
|Balberith||A Devil created by Hades from using Lilith’s flesh and Book of Lucifer||Super Devil||Pure-Blooded Devil||Alive (Defected)|
|Verrine||A Devil created by Hades from using Lilith’s flesh and Book of Lucifer||Super Devil||Pure-Blooded Devil||Alive (Defected)|
|Zeno||A Grim Reaper serving under Hades, former leader of Team Black Satan of Darkness Dragon King||High-Class Grim Reaper||Grim Reaper||Alive (Defected)|
|Hidden Khaos Brigade||Remnants of the original members of the Khaos Brigade that have gone underground and hidden their identities in order to leak information about Team DxD to their enemies||N/A||Various||Active|
|Nebiros||It was one of the six households that directly served the previous Satan Lucifer||N/A||Pure-Blooded Devil||Active|
|Meredith Ordinton||A former Golden Dawn Magician, who is related to the British Royal Family. She is the possessor of one of the 5 newly manifested Longinus; Alphecca Tyrant||N/A||Human (Magician)||Alive (In Grigori custody)|
- In the Volume 24, Loki’s daughter Hel, King Enma and Indra were mentioned as candidates who could join them.
- King Enma and Indra were considered to be very strict gods, so cooperation with them would have been highly unlikely.