The story begins in the great war of 1917.
This begins an approximately 50 year conflict of harsh war tactics against all of the nations. This unfortunately leaves the world in ruins and all of civilization as humans knew it was destroyed.
At least, that's what it seemed. There were still small tribes and groups wandering the world, but no direct civilized people as we know it.
The eco-system was slowly being destroyed, dust storms destroying cities, and global warming finishing the planet.
A disease known as the red death doesn't help the situation either, killing over half what is left of the planets population. This leads to desperate Conquests against tribes searching for medicine and supplies.
After the "Age of Dust", humans begin to recover and relieve industrial society. During this time a man known as Gabriel created the first airship since the great war. He becomes the first and best airship captain (as known in the first Guns of Icarus) of the time. But his journey ends in ruin when he returns to his home city and sees it has been destroyed by pirates. He finds the pirates but then himself is lost along with his airship.
Although this was a major setback, it still gave wind to the "Age of Air". Gabriels work was reverse engineered giving birth to a new breed of airships (As known from GOI Online). This brings back much of society and political dominance is restored.
87 Years after Gabriel and his Icarus, the skies are dominated be airships from 6 different factions (Anglean Republic - Fjord Baronies - Order of Chaladon - Yesha Empire - Arashi League - and the Mercantile Guild).
This brings everything up to speed on where Guns of Icarus is today. There will surely be more to the story as time progresses, but for now, this is as far into the world as we can see.