Warzone: Iron Wolf II's development started after the completion of Warzone: Iron Wolf under the codename Project Sleeper. Sleeper was originaly not conceived as a Warzone entry at all, but rather a multimedia project. Elements of this were quickly cut due to scope and the project was rebranded into version 2.0 or Inglorious.
Inglorious was at first set in a new continuity and feature a complete new cast of characters. The first campaign prototypes were made during this version. However, the studio felt that the game required too much background informatiom to be justified and settled on making the game a direct sequel to Iron Wolf.
The studio started fleshing out the lore during this version of the game, version 3.0. Elements and assets of the Inglorious campaign were reused, albeit it being that holding on to previous ideas made it more difficult to get a coherent story. The studio got together with the publisher and explained that they needed to put more effort on the campaign mode, wanting to branch out the things to do in it.
This led to Elegant Attack being added to the development team, with them handling some aspects of the multiplayer, like map design and charactet animations. The team had more freedom in designing the multiplayer, as DECA gave them the lore of the world and let them make their intepretation of locations and factions. This means that multiplayer maps are not tied to campaign missions.
DECA felt that Iron Wolf II required a lot of story telling to make the story in general understandable, the team considered multiple media during development. Eventually, they created a series of short stories, a prequel comic and more to detail the events before the game, as well as lengthier cutscenes in between missions.
Warzone: Iron Wolf II takes elements from it's prequel and spiritual predecessor and expands heavily on mechanics like movement and customization. While it's campaign, albeit being expanded on as in the sense of quantity, hasn't changed that much compared to its predecessors, multiplayer takes a step into the direction of the old Arena-shooter genre instead of the Military-shooter genre.
The campaign starts in 2042, 9 years after the events of Iron Wolf. In 2039, the Geneva Convention on World Peace is held in Geneva, Switzerland. This results in the formation of the Geneva Convention Defense Protocol, at first a United Nations-backed organization. Due to rules of the convention in regards to a Nations Arms possession, the United States, China and more leave the Protocol. The United States is afraid that Typhoon will be protected by the Convention and thus wants to take matters in their own hands, while China decides to support the United States. The creates the establishment of the Sovereignity Pact. GCDP Operation Force Vanguard is established as the primary defense unit as a successor to the Blue Helmets, engaging in peacekeeping missions across the world. Meanwhile, the United States are continuing their chase after Typhoon remnants, making the 2 factions bound to collide into each other.