The Green Storm is a fanatical splinter group of the Anti-Traction League, which ends up in control of the
League. Its primary objective is to destroy all Traction Cities and "make the world green again", since the Traction Cities' constant movement and hunting for resources long ago destroyed much of the world's vegetation. The symbol of the Green Storm is a jagged green lightning bolt. The Green Storm's rule is portrayed as militaristic, totalitarian and absolute, tolerating no dissent.
It originally developed as a secret organisation consisting of disaffected and revanchist Anti-Traction League officers formed in response to the destruction of the League's Northern Air-Fleet at Batmunkh Gompa by London agent Thaddeus Valentine and the loss of the Spitzbergen Static due to Arkangel attacking it in the gap between Mortal Engines and Predators Gold. However, it could have even existed before then, as Anti-Tractionists who didn't want to just live in their own lands but 'take back' those of the traction cities.
Two years following the destruction of London, a squadron of Green Storm fighter airships pursue Tom and Hester in the Jenny Haniver. Later, an agent of the Green Storm kidnaps Hester Shaw in Arkangel and transports her to one of their Arctic bases. It is revealed in the book that the Green Storm are not as reluctant to use "Old Tech" as most other Anti-Tractionists, for they use a surviving London Engineer named Popjoy to build armies of Stalkers.
Interestingly, the same Engineer also managed to resurrect Anna Fang as the Stalker Fang. Unfortunately, the Stalker Fang did not ever regain a former identity, although she eventually became the leader of the Green Storm. In the following summer, the Green Storm overthrows the ruling High Council and takes over the Anti-Traction League.
Over the next fifteen years, the Green Storm under the leadership of the Stalker Fang is revealed to have conquered half of the known world with its vast legions of Stalkers, fighter airships and Air Destroyers. During that time, the Green Storm had waged a long war against the Traction Cities.
The Green Storm also has a specialist branch of its military called the Resurrection Corps, which is in charge of the resurrection of dead corpses into Stalkers in support of the Green Storm's war against the cities. It was founded by the same former London engineer that had resurrected her. Dr Popjoy also became her personal surgeon-mechanic.
However, the Stalker Fang was also interested in an ancient artefact from Anchorage called the "Tin Book", which was written in an ancient military code. Wren Natsworthy, the daughter of Tom and Hester Natsworthy, had managed to leave Anchorage-in-Vineland only to get enslaved in Brighton and sold as a slave to Nimrod Pennyroyal. During her journey, she managed to bring the Tin Book though it became the property of Pennyroyal.
However, an agent of the Green Storm, Agent 28, discovered the Tin Book and alerted her mistress by sending a "resurrected" seagull, a Raptor, carrying a message to the Green Storm's capital, Tienjing. Later, the Green Storm attacked Brighton and retrieved the document. During the raid, their leader was assassinated and the document destroyed in the process. Following that, her second-in-command General Naga assumed command. It was assumed that the Green Storm was responsible for the crash of the Jenny Haniver. After Naga's death in A Darkling Plain, the Green Storm was disbanded and the Anti-Traction League refounded by Oenone Zero.