drakkeon

Drakkeon is gas with several unique properties that make it invaluable as a lifting gas for airships. Drakkeon is extremely buoyant, being able to lift dozens of times as much as hydrogen or helium. It is also very cheap to produce, to the point where all airships have drakkeon producing machines inside of them that allow for their gas bags to inflate and deflate mid-flight. Drakkeon is also almost completely non-flammable, and it can only be ignited if it's continuously exposed to a large, hot flame.
Drakkeon is also what allows stratozoans to float through the air, their many internal bags full of naturally produced drakkeon allow them to live their entire lives in the skies, never needing to even go near the ground, let alone land on it. Drakkeon was also discovered by when the Merindian Empire, in search for a way to build better airships studied what stratozoans use to float and how they create and store it.